Paul Boddie's Free Software-related blog

As noted previously, two of my interests in recent times have been computing history and microkernel-based operating systems. Having perused academic and commercial literature in the computing field a fair amount over the last few years, I experienced some feelings of familiarity when looking at the schedule for FOSDEM, which took place earlier in the year, brought about when encountering a talk in the “microkernel and component-based OS” developer room: “A microkernel-based orchestrator for distributed Internet services?”

In this talk’s abstract, mentions of the complexity of current Linux-based container solutions led me to consider the role of containers and virtual machines. In doing so, it brought back a recollection of a paper published in 1996, “Microkernels Meet Recursive Virtual Machines”, describing a microkernel-based system architecture called Fluke. When that paper was published, I was just starting out in my career and preoccupied with other things. It was only in pursuing those interests of mine that it came to my attention more recently.

It turned out that there were others at FOSDEM with similar concerns. Liam Proven, who regularly writes about computing history and alternative operating systems, gave a talk, “One way forward: finding a path to what comes after Unix”, that combined observations about the state of the computing industry, the evolution of Unix, and the possibilities of revisiting systems such as Plan 9 to better inform current and future development paths. This talk has since been summarised in four articles, concluding with “A path out of bloat: A Linux built for VMs” that links back to the earlier parts.

Both of these talks noted that in attempting to deploy applications and services, typically for Internet use, practitioners are now having to put down new layers of functionality to mitigate or work around limitations in existing layers. In other words, they start out with an operating system, typically based on Linux, that provides a range of features including support for multiple users and the ability to run software in an environment largely confined to the purview of each user, but end up discarding most of this built-in support as they bundle up their software within such things as containers or virtual machines, where the software can pretend that it has access to a complete environment, often running under the control of one or more specific user identities within that environment.

With all this going on, people should be questioning why they need to put one bundle of software (their applications) inside another substantial bundle of software (an operating system running in a container or virtual machine), only to deploy that inside yet another substantial bundle of software (an operating system running on actual hardware). Computing resources may be the cheapest they have ever been, supply chain fluctuations notwithstanding, but there are plenty of other concerns about building up levels of complexity in systems that should prevent us from using cheap computing as an excuse for business as usual.

A Quick Historical Review

In the early years of electronic computing, each machine would be dedicated to running a single program uninterrupted until completion, producing its results and then being set up for the execution of a new program. In this era, one could presumably regard a computer simply as the means to perform a given computation, hence the name.

However, as technology progressed, it became apparent that dedicating a machine to a single program in this way utilised computing resources inefficiently. When programs needed to access relatively slow peripheral devices such as reading data from, or writing data to, storage devices, the instruction processing unit would be left idle for significant amounts of cumulative time. Thus, solutions were developed to allow multiple programs to reside in the machine at the same time. If a running program had paused to allow data to transferred to or from storage, another program might have been given a chance to run until it also found itself needing to wait for those peripherals.

In such systems, each program can no longer truly consider itself as the sole occupant or user of the machine. However, there is an attraction in allowing programs to be written in such a way that they might be able to ignore or overlook this need to share a computer with other programs. Thus, the notion of a more abstract computing environment begins to take shape: a program may believe that it is accessing a particular device, but the underlying machine operating software might direct the program’s requests to a device of its own choosing, presenting an illusion to the program.

Although these large, expensive computer systems then evolved to provide “multiprogramming” support, multitasking, virtual memory, and virtual machine environments, it is worth recalling the evolution of computers at the other end of the price and size scale, starting with the emergence of microcomputers from the 1970s onwards. Constrained by the availability of affordable semiconductor components, these small systems at first tended to limit themselves to modest computational activities, running one program at a time, perhaps punctuated occasionally by interrupts allowing the machine operating software to update the display or perform other housekeeping tasks.

As microcomputers became more sophisticated, so expectations of the functionality they might deliver also became more sophisticated. Users of many of the earlier microcomputers might have run one application or environment at a time, such as a BASIC interpreter, a game, or a word processor, and what passed for an operating system would often only really permit a single application to be active at once. A notable exception in the early 1980s was Microware’s OS-9, which sought to replicate the Unix environment within the confines of 8-bit microcomputer architecture, later ported to the Motorola 68000 and used in, amongst other things, Philips’ CD-i players.

OS-9 offered the promise of something like Unix on fairly affordable hardware, but users of systems with more pedestrian software also started to see the need for capabilities like multitasking. Even though the dominant model of microcomputing, perpetuated by the likes of MS-DOS, had involved running one application to do something, then exiting that application and running another, it quickly became apparent that users themselves had multitasking impulses and were inconvenienced by having to finish off something, even temporarily, switch to another application offering different facilities, and then switch back again to resume their work.

Thus, the TSR and the desk accessory were born, even finding a place on systems like the Apple Macintosh, whose user interface gave the impression of multitasking functionality and allowed switching between applications, even though only a single application could, in general, run at a time. Later, Apple introduced MultiFinder with the more limited cooperative flavour of multitasking, in contrast to systems already offering preemptive multitasking of applications in their graphical environments. People may feel the compulsion to mention the Commodore Amiga in such contexts, but a slightly more familiar system from a modern perspective would be the Torch Triple X workstation with its OpenTop graphical environment running on top of Unix.

The Language System Phenomenon

And so, the upper and lower ends of the computing market converged on expectations that users might be able to run many programs at a time within their computers. But the character of these expectations might have been coloured differently from the prior experiences of each group. Traditional computer users might well have framed the environment of their programs in terms of earlier machines and environments, regarding multitasking as a convenience but valuing compatibility above all else.

At the lower end of the market, however, users were looking to embrace higher-level languages such as Pascal and Modula-2, these being cumbersome on early microprocessor systems but gradually becoming more accessible with the introduction of later systems with more memory, disk storage and processors more amenable to running such languages. Indeed, the notion of the language environment emerged, such as UCSD Pascal, accompanied by the portable code environment, such as the p-System hosting the UCSD Pascal environment, emphasising portability and defining a machine detached from the underlying hardware implementation.

Although the p-System could host other languages, it became closely associated with Pascal, largely by being the means through which Pascal could be propagated to different computer systems. While 8-bit microcomputers like the BBC Micro struggled with something as sophisticated as the p-System, even when enhanced with a second processor and more memory, more powerful machines could more readily bear the weight of the p-System, even prompting some to suggest at one time that it was “becoming the de facto standard operating system on the 68000”, supplied as standard on 68000-based machines like the Sage II and Sage IV.

Such language environments became prominent for a while, Lisp and Smalltalk being particularly fashionable, and with the emergence of the workstation concept, new and divergent paths were forged for a while. Liam Proven previously presented Wirth’s Oberon system as an example of a concise, efficient, coherent environment that might still inform the technological direction we might wish to take today. Although potentially liberating, such environments were also constraining in that their technological homogeneity – the imposition of a particular language or runtime – tended to exclude applications that users might have wanted to run. And although Pascal, Oberon, Lisp or Smalltalk might have their adherents, they do not all appeal to everyone.

Indeed, during the 1980s and even today, applications sell systems. There are plenty of cases where manufacturers ploughed their own furrow, believing that customers would see the merits in their particular set of technologies and be persuaded into adopting those instead of deploying the products they had in mind, only to see the customers choose platforms that supported the products and technologies that they really wanted. Sometimes, vendors doubled down on customisations to their platforms, touting the benefits of custom microcode to run particular programs or environments, ignoring that customers often wanted more generally useful solutions, not specialised products that would become uncompetitive and obsolete as technology more broadly progressed.

For all their elegance, language-oriented environments risked becoming isolated enclaves appealing only to their existing users: an audience who might forgive and even defend the deficiencies of their chosen systems. For example, image-based persistence, where software could be developed in a live environment and “persisted” or captured in an image or “world” for later use or deployment, remains a tantalising approach to software development that sometimes appeals to outsiders, but one can argue that it also brings risks in terms of reproducibility around software development and deployment.

If this sounds familiar to anyone old enough to remember the end of the 1990s and the early years of this century, probing this familiarity may bring to mind the Java bandwagon that rolled across the industry. This caused companies to revamp their product lines, researchers to shelve their existing projects, developers to encounter hostility towards the dependable technologies they were already using, and users to suffer the mediocre applications and user interfaces that all of this upheaval brought with it.

Interesting research, such as that around Fluke and similar projects, was seemingly deprioritised in favour of efforts that presumably attempted to demonstrate “research relevance” in the face of this emerging, everything-in-Java paradigm with its “religious overtones”. And yet, commercial application of supposedly viable “pure Java” environments struggled in the face of abysmal performance and usability.

The Nature of the Machine

Users do apparently value heterogeneity or diversity in their computing environments, to be able to mix and match their chosen applications, components and technologies. Today’s mass-market computers may have evolved from the microcomputers of earlier times, accumulating workstation, minicomputer and mainframe technologies along the way, and they may have incorporated largely sensible solutions in doing so, but it can still be worthwhile reviewing how high-end systems of earlier times addressed issues of deploying different kinds of functionality safely within the same system.

When “multiprogramming” became an essential part of most system vendors’ portfolios, the notion of a “virtual machine” emerged, this being the vehicle through which a user’s programs could operate or experience the machine while sharing it with other programs. Today, using our minicomputer or Unix-inspired operating systems, we think of a virtual machine as something rather substantial, potentially simulating an entire system with all its peculiarities, but other interpretations of the term were once in common circulation.

In the era when the mainframe reigned supreme, their vendors differed in their definitions of a virtual machine. International Computers Limited (ICL) revamped their product range in the 1970s in an attempt to compete with IBM, introducing their VME or Virtual Machine Environment operating system to run on their 2900 series computers. Perusing the literature related to VME reveals a system that emphasises different concepts to those we might recognise from Unix, even though there are also many similarities that are perhaps obscured by differences in terminology. Where we are able to contrast the different worlds of VME and Unix, however, is in the way that ICL chose to provide a Unix environment for VME.

As the end of the 1980s approached, once dominant suppliers with their closed software and solution ecosystems started to get awkward questions about Unix and “open systems”. The less well-advised, like Norway’s rising star, Norsk Data, refused to seriously engage with such trends, believing their own mythology of technological superiority, until it was too late to convince their customers switching to other platforms that they had suddenly realised that this Unix thing was worthwhile after all. ICL, meanwhile, only tentatively delivered a Unix solution for their top-of-the-line systems.

Six years after ICL’s Series 39 mainframe range was released, and after years of making a prior solution selectively available, ICL’s VME/X product was delivered, offering a hosted Unix environment within VME, broadly comparable with Amdahl’s UTS and IBM’s IX/370. Eventually, VME/X was rolled into OpenVME, acknowledging “open systems” rather like Digital’s OpenVMS, all without actually being open, as one of my fellow students once joked. Nevertheless, VME/X offers an insight into what a virtual machine is in VME and how ICL managed to map Unix concepts into VME.

Reading VME documentation, one gets the impression that, fundamentally, a virtual machine in the VME sense is really about giving an environment to a particular user, as opposed to a particular program. Each environment has its own private memory regions, inaccessible to other virtual machines, along with other regions that may be shared between virtual machines. Within each environment, a number of processes can be present, but unlike Unix processes, these are simply execution contexts or, in Unix and more general terms, threads.

Since the process is the principal abstraction in Unix through which memory is partitioned, it is curious that in VME/X, the choice was made to not map Unix processes to VME virtual machines. Instead, each “terminal user”, each “batch job” (not exactly a Unix concept), as well as “certain daemons” were given their own virtual machines. And when creating a new Unix process, instead of creating a new virtual machine, VME/X would in general create a new VME process, seemingly allowing each user’s processes to reside within the same environment and to potentially access each other’s memory. Only when privilege or user considerations applied, would a new process be initiated in a new virtual machine.

Stranger than this, however, is VME’s apparent inability to run multiple processes concurrently within the same virtual machine, even on multiprocessor systems, although processes in different virtual machines could run concurrently. For one process to suspend execution and yield to another in the same virtual machine, a special “process-switching call” instruction was apparently needed, providing a mechanism like that of green threads or fibers in other systems. However, I could imagine that this could have provided a mechanism for concealing each process’s memory regions from others by using this call to initiate a reconfiguration of the memory segments available in the virtual machine.

I have not studied earlier ICL systems, but it would not surprise me if the limitations of this environment resembled those of earlier generations of products, where programs might have needed to share a physical machine graciously. Thus, the heritage of the system and the expectations of its users from earlier times appear to have survived to influence the capabilities of this particular system. Yet, this Unix implementation was actually certified as compliant with the X/Open Portability Guide specifications, initially XPG3, and was apparently the first system to have XPG4 base compliance.

Partitioning by User

A tour of a system that might seem alien or archaic to some might seem self-indulgent, but it raises a few useful thoughts about how systems may be partitioned and the sophistication of such partitioning. For instance, VME seems to have emphasised partitioning by user, and this approach is a familiar and mature one with Unix systems, too. Traditionally, dedicated user accounts have been set up to run collections of associated programs. Web servers often tend to run in a dedicated account, typically named “apache” or “httpd”. Mail servers and database servers also tend to follow such conventions. Even Android has used distinct user accounts to isolate applications from each other.

Of course, when partitioning functionality by user in Unix systems, one must remember that all of the processes involved are isolated from each other, in that they do not share memory inadvertently, and that the user identity involved is merely associated with these processes: it does not provide a container for them in its own right. Indeed, the user abstraction is simply the way that access by these processes to the rest of the system is controlled, largely mediated by the filesystem. Thus, any such partitioning arrangement brings the permissions and access control mechanisms into consideration.

In the simplest cases, such as a Web server needing to be able to read some files, the necessary adjustments to groups or even the introduction of access control lists can be sufficient to confine the Web server to its own territory while allowing other users and programs to interact with it conveniently. For example, Web pages can be published and updated by adding, removing and changing files in the Web site directories given appropriate permissions. However, it is when considering the combination of servers or services, each traditionally operating under their own account, that administrators start to consider alternatives to such traditional approaches.

Let us consider how we might deploy multiple Web applications in a shared hosting environment. Clearly, it would be desirable to give all of these applications distinct user accounts so that they would not be able to interfere with each other’s files. In a traditional shared hosting environment, the Web application software itself might be provided centrally, with all instances of an application relying on the same particular version of the software. But as soon as the requirements for the different instances start to diverge – requiring newer or older versions of various components – they become unable to rely entirely on the centrally provided software, and alternative mechanisms for deploying divergent components need to be introduced.

To a customer of such a service having divergent requirements, the provider will suggest various recipes for installing new software, often involving language-specific packaging or building from source, with compilers available to help out. The packaging system of the underlying software distribution is then mostly being used by the provider itself to keep the operating system and core facilities updated. This then leads people to conclude that distribution packaging is too inflexible, and this conclusion has led people in numerous directions to try and address the apparently unmet needs of the market, as well as to try and pitch their own particular technology as the industry’s latest silver bullet.

There is arguably nothing to stop anyone deploying applications inside a user’s home directory or a subdirectory of the home directory, with /home/user/etc being the place where common configuration files are stored, /home/user/var being used for some kind of coordination, and so on. Many applications can be configured to work in another location. One problem is that this configuration is sometimes fixed within the software when it is built, meaning that generic packages cannot be produced and deployed in arbitrary locations.

Another is that many of the administrative mechanisms in Unix-like systems favour the superuser, rely on operating on software configured for specific, centralised locations, and only really work at the whole-machine level with a global process table, a global set of user identities, and so on. Although some tools support user-level activities, like the traditional cron utility, scheduling jobs on behalf of users, as far as I know, traditional Unix-like systems have never really let users define and run their own services along the same lines as is done for the whole system, administered by the superuser.

Partitioning by Container

If one still wants to use nicely distribution-packaged software on a per-user, per-customer or per-application basis, what tends to happen is that an environment is constructed that resembles the full machine environment, with this kind of environment existing in potentially many instances on the same system. In other words, just so that, say, a Debian package can be installed independently of the host system and any of its other users, an environment is constructed that provides directories like /usr, /var, /etc, and so on, allowing the packaging system to do its work and to provide the illusion of a complete, autonomous machine.

Within what might be called the Unix traditions, a few approaches exist to provide this illusion to a greater or lesser degree. The chroot mechanism, for instance, permits the execution of programs that are generally only able to see a section of the complete filesystem on a machine, located at a “changed root” in the full filesystem. By populating this part of the filesystem with files that would normally be found at the top level or root of the normal filesystem, programs invoked via the chroot mechanism are able to reference these files as if they were in their normal places.

Various limitations in the scope of chroot led to the development of such technologies as jails, Linux-VServer and numerous others, going beyond filesystem support for isolating processes, and providing a more comprehensive illusion of a distinct machine. Here, systems like Plan 9 showed how the Unix tradition might have evolved to support such needs, with Linux and other systems borrowing ideas such as namespaces and applying them in various, sometimes clumsy, ways to support the configuration of program execution environments.

Going further, technologies exist to practically simulate the experience of an entirely separate machine, these often bearing the “virtual machine” label in the vocabulary of our current era. A prime example of such a technology is KVM, available on Linux with the right kind of processor, which allows entire operating systems to run within another. Using a virtual machine solution of this nature is something of a luxury option for an application needing its own environment, being able to have precisely the software configuration of its choosing right down to the level of the kernel. One disadvantage of such full-fat virtual machines is the amount of extra software involved and those layers upon layers of programs and mechanisms, all requiring management and integration.

Some might argue for solutions where the host environment does very little and where everything of substance is done in one kind of virtual machine or other. But if all the virtual machines are being used to run the same general technology, such as flavours of Linux, one has to wonder whether it is worth keeping a distinct hypervisor technology around. That might explain the emergence of KVM as an attempt to have Linux act as a kind of hypervisor platform, but it does not excuse a situation where the hosting of entire systems is done in preference to having a more configurable way of deploying applications within Linux itself.

Some adherents of hypervisor technologies advocate the use of unikernels as a way of deploying lightweight systems on top of hypervisors, specialised to particular applications. Such approaches seem reminiscent of embedded application deployment, with entire systems being built and tuned for precisely one job: useful for some domains but not generally applicable or particularly flexible. And it all feels like the operating system is just being reinvented in a suboptimal, ad-hoc fashion. (Unikernels seem to feature prominently in the “microkernel and component-based OS” developer room at FOSDEM these days.)

Then there is the approach advocated in Liam Proven’s talk, of stripping down an operating system for hypervisor deployment, which would need to offer a degree of extra flexibility to be more viable than a unikernel approach, at least when applied to the same kinds of problems. Of course, this pushes hardware support out of the operating system and into the realm of the hypervisor, which could be beneficial if done well, or it could imperil support for numerous hardware platforms and devices due to numerous technological, economic and social reasons. Liam advocates pushing filesystem support out of the kernel, and potentially out of the operating system as well, although it is not clear what would then need to take up that burden and actually offer filesystem facilities.

Some Reflections

This is where we may return to those complaints about the complexity of modern hosting frameworks. That a need for total flexibility in every application’s software stack presents significant administrative challenges. But in considering the nature of the virtual machine in its historical forms, we might re-evaluate what kind of environment software really needs.

In my university studies, a project of mine investigated a relatively hot topic at the time: mobile software agents. One conclusion I drew from the effort was that programs could be written to use a set of well-defined interfaces and to potentially cooperate with other programs, without thousands of operating system files littering their shared environment. Naturally, such programs would not be running by magic: they would need to be supported by infrastructure that allows them to be loaded and executed, but all of this infrastructure can be maintained outside the environment seen by these programs.

At the time, I relied upon the Python language runtime for my agent programs with its promising but eventually inadequate support for safe execution to prevent programs from seeing the external machine environment. Most agent frameworks during this era were based on particular language technologies, and the emergence of Java only intensified the industry’s focus on this kind of approach, naturally emphasising Java, although Inferno also arrived at around this time and offered a promising, somewhat broader foundation for such work than the Java Virtual Machine.

In the third part of his article series, Liam Proven notes that Plan 9, Inferno’s predecessor, is able to provide a system where “every process is in a container” by providing support for customisable process namespaces. Certainly, one can argue that Plan 9 and Inferno have been rather overlooked in recent years, particularly by the industry mainstream. He goes on to claim that such functionality, potentially desirable in application hosting environments, “makes the defining features of microkernels somewhat irrelevant”. Here I cannot really agree: what microkernels actually facilitate goes beyond what a particular operating system can do and how it has been designed.

A microkernel-based approach not only affords the opportunity to define the mechanisms of any resulting system, but it also provides the ability to define multiple sets of mechanisms, all of them potentially available at once, allowing them to be investigated, compared, and even combined. For example, Linux retains the notion of a user of the system, maintaining a global registry of such users, and even with notionally distinct sets of users provided by user namespaces, cumbersome mappings are involved to relate those namespace users back to this global registry. In a truly configurable system, there can be multiple user authorities, each being accessible by an arbitrary selection of components, and some components can be left entirely unaware of the notion of a user whatsoever.

Back in the 1990s, much coverage was given to the notion of operating system personalities. That various products would, for example, support DOS or Windows applications as well as Macintosh ones or Unix ones or OS/2 ones. Whether the user interface would reflect this kind of personality on a global level or not probably kept some usability professionals busy, and I recall one of my university classmates talking about a system where it was apparently possible to switch between Windows or maybe OS/2 and Macintosh desktops with a key combination. Since his father was working at IBM, if I remember correctly, that could have been an incarnation of IBM’s Workplace OS.

Other efforts were made to support multiple personalities in the same system, potentially in a more flexible way than having multiple separate sessions, and certainly more flexible than just bundling up, virtualising or emulating the corresponding environments. Digital investigated the porting of VMS functionality to an environment based on the Mach 3.0 microkernel and associated BSD Unix facilities. Had Digital eventually adopted a form of OSF/1 based on Mach 3.0, it could have conceivably provided a single system running Unix and VMS software alongside each other, sharing various common facilities.

Regardless of one’s feelings about Mach 3.0, whether one’s view of microkernels is formed from impressions of an infamous newsgroup argument from over thirty years ago, or whether it considers some of the developments in the years since, combining disparate technologies in a coherent fashion within the same system must surely be a desirable prospect. Being able to do so without piling up entire systems on top of each other and drilling holes between the layers seems like a particularly desirable thing to do.

A flexible, configurable environment should appeal to those in the same position as the FOSDEM presenter wishing to solve his hosting problems with pruned-down software stacks, as well as appealing to anyone with their own unrealised ambitions for things like mobile software agents. Naturally, such a configurable environment would come with its own administrative overheads, like the need to build and package applications for deployment in more minimal environments, and the need to keep software updated once deployed. Some of that kind of work should arguably get done under the auspices of existing distribution frameworks and initiatives, as opposed to having random bundles of software pushed to various container “hubs” posing as semi-official images, all the while weighing down the Internet with gigabytes of data constantly scurrying hither and thither.

This article does not propose any specific solution or roadmap for any of this beyond saying that something should indeed be done, and that microkernel-based environments, instead of seeking to reproduce Unix or Windows all over again, might usefully be able to provide remedies that we might consider. And with that, I suppose I should get back to my own experiments in this area.

Since my last update, I have been able to spend some time gradually broadening and hopefully improving the support for classic programming interfaces in my L4Re-based experiments, centred around a standard C library implementation based on Newlib. Of course, there were some frustrations experienced along the way, and much remains to be done, not only in terms of new functionality that will need to be added, but also verification and correction of the existing functionality as I come to realise that I have made mistakes, these inevitably leading to new frustrations.

One area I previously identified for broadened support was that of process creation and the ability to allow programs to start other programs. This necessitated a review of the standard C process control functions, which are deliberately abstracted from the operating system and are much simpler and more constrained than those found in the unistd.h file that Unix programmers might be more familiar with. The traditional Unix functions are very much tied up with the Unix process model, and there are some arguments to be made that despite being “standard”, these functions are a distraction and, in various respects, undesirable from a software architecture perspective, for both applications and the operating systems that run them.

So, ignoring the idea that I might support the likes of execl, execv, fork, and so on, I returned to consideration of the much more limited system function that is part of the C language standards, this simply running an abstract command provided by a character string and returning a result code when the command has completed:

int system(const char *command);

To any casual application programmer, this all sounds completely reasonable: they embed a command in their code that is then presented to “the system”, which runs the commands and hands back a result or status code. But those of us who are accustomed to running commands at the shell and in our own programs might already be picking apart this simple situation.

First of all, “the system” needs to have what the C standards documentation calls a “command processor”. In fact, even Unix standardisation efforts have adopted the term, despite the Linux manual pages referring to “the shell”. But at this point, my own system does not have a shell or a command processor, instead providing only a process server that manages the creation of new processes. And my process server deals with arrays or “vectors” of strings that comprise a command to be used to run a given program, configured by a sequence of arguments or parameters.

Indeed, this brings us to some other matters that may be familiar to anyone who has had the need to run commands from within programs: that of parameterising command invocations by introducing our own command argument values; and that of making sure that the representation of the program name and its arguments do not cause the shell to misinterpret these elements, by letting an errant space character break the program name into two, for instance. When dealing only with command strings, matters of quoting and tokenisation enter the picture, making the exercise very messy indeed.

So, our common experience has provided us with a very good reason to follow the lead of the classic execv Unix function and to avoid the representational issues associated with command string processing. In this regard, the Python standard library has managed to show the way in some respects, introducing the subprocess module which features interfaces that are equivalent to functions like system and popen, supporting the use of both command strings and lists of command elements to represent the invoked command.

Oddly, however, nobody seems to provide a “vector” version of the system function at the C language level, but it seemed to be the most natural interface I might provide in my own system:

int systemv(int argc, const char *argv[]);

I imagine that those doing low-level process creation in a Unix-style environment would be content to use the exec family of functions, probably in conjunction with the fork function, precisely because a function like execv “shall replace the current process image with a new process image”, as the documentation states. Obviously, replacing the current process isn’t helpful when implementing the system function because it effectively terminates the calling program, whereas the system function is meant to allow the program to continue after command completion. So, fork has to get involved somehow.

The Flow of Convention

I get the impression that people venturing along a similar path to mine are often led down the trail of compatibility with the systems that have gone before, usually tempted by the idea that existing applications will eventually be content to run on their system without significant modification, and thus an implementer will be able to appeal to an established audience. In this case, the temptation is there to support the fork function, the exec semantics, and to go with the flow of convention. And sometimes, a technical obstacle seems like a challenge to be met, to show that an implementation can provide support for existing software if it needs or wants to.

Then again, having seen situations where software is weighed down by the extra complexity of features that people believe it should have, some temptations are best resisted, perhaps with a robust justification for leaving out any particular supposedly desirable feature. One of my valued correspondents pointed me to a paper by some researchers that provides a robust argument for excluding fork and for promoting alternatives. Those alternatives have their shortcomings, as noted in the paper, and they seem rather complicated when considering simple situations like merely creating a completely separate process and running a new program in it.

Of course, there may still be complexity in doing simple things. One troublesome area was that of what might happen to the input and output streams of a process that creates another one: should the new process be able to receive the input that has been sent to the creating process, and should it be able to send its output to the recipient of the creating process’s output? For something like system or systemv, the initial “obvious” answer might be the total isolation of the created process from any existing input, but this limits the usefulness of such functions. It should arguably be possible to invoke system or systemv within a program that is accepting input as part of a pipeline, and for a process created by these functions to assume the input processing role transparently.

Indeed, the Unix world’s standards documentation for system extends the C standard to assert that the system function should behave like a combination of fork and execl, invoking the shell utility, sh, to initiate the program indicated in the call to system. It all sounds a bit prescriptive, but I suppose that what it largely means is that the input and output streams should be passed to the initiated program. A less prescriptive standard might have said that, of course, but who knows what kind of vendor lobbying went on to avoid having to modify the behaviour of those vendors’ existing products?

This leads to the awkward problem of dealing with the state of an input stream when such a stream is passed to another process. If the creating process has already read part of a stream, we need the newly created process to be aware of the extent of consumed data so that it may only read unconsumed data itself. Similarly, the newly created process must be able to append output to the existing output stream instead of overwriting any data that has already been written. And when the created process terminates, we need the creating process to synchronise its own view of the input and output streams. Such exercises are troublesome but necessary to provide predictable behaviour at higher levels in the system.

Some Room for Improvement

Another function that deserves revisiting is the popen function which either employs a dedicated output stream to capture the output of a created process within a program, or a dedicated input stream so that a program can feed the process with data it has prepared. The mode indicates what kind of stream the function will provide: “r” yields an output stream passing data out of the process, “w” yields an input stream passing data into the process.

FILE *popen(const char *command, const char *mode);

This function is not in the C language standards but in Unix-related standards, but it is too useful to ignore. Like the system function, the standards documentation also defines this function in terms of fork and execl, with the shell getting involved again. Not entirely obvious from this documentation is what happens with the stream that isn’t specified, however, but we can conclude that with its talk of input and output filters, as well as the mention of those other functions, that if we request an output stream from the new process, the new process will acquire standard input from the creating process as its own input stream. Correspondingly, if we request an input stream to feed the new process, the new process will acquire standard output for itself and write output to that.

This poses some concurrency issues that the system function largely avoids. Since the system function blocks until the created process is completed, the state of the shared input and output streams can be controlled. But with popen, the created process runs concurrently and can interact with whichever stream it acquired from the creating process, just as the creating process might also be using it, at least until pclose is invoked to wait for the completion of the created process. The standards documentation and the Linux manual page both note such pitfalls, but the whole business seems less than satisfactory.

Again, the Python standard library shows what a better approach might be. Alongside the popen function, the popen2 function creates dedicated input and output pipes for interaction with the created process, the popen3 function adds an error pipe to the repertoire, and there is even a popen4 function that presumably does what some people might expect from popen2, merging the output and error streams into a single stream. Naturally, this was becoming a bit incoherent, and so the subprocess module was brought in to clean it all up.

Our own attempt at a cleaner approach might involve the following function:

pid_t popenv(int argc, const char *argv[], FILE **input, FILE **output, FILE **error);

Here, we want to invoke a program using a vector containing the program and arguments, just as we did before, but we also want to acquire the input, output and error streams. However, we might allow any of these to be specified as NULL, indicating that any such stream will not be opened for the created process. Since this might cause problems, we might need to create special “empty” or “null” streams, where appropriate, so as not to upset the C library.

Unlike popen, we might also provide the process identifier for the created process. This would allow us to monitor the process, control it in some way, and to wait for its completion. The nature of a process identifier is potentially more complicated than one might think, especially in my own system where there can be many process servers, each of them creating new processes without any regard to the others.

A Simpler Portable Environment Standard

Maybe I am just insufficiently aware of the historical precedents in this regard, but it seems that while C language standards are disappointingly tame when it comes to defining interaction with the host environment, the Unix or POSIX standardisation efforts go into too much detail and risk burdening any newly designed system with the baggage of systems that happened to be commercially significant at a particular point in time. Windows NT infamously feigned compliance with such standards to unlock the door to lucrative government contracts and to subvert public software procurement processes, generating colossal revenues that easily paid for any inconvenient compliance efforts. However, for everybody else, such standards seem to encumber system and application developers with obligations and practices that could be refined, improved and made more suitable for modern needs.

My own work depends on L4Re which makes extensive use of capabilities to provide access to entities within the system. For example, each process relies on a task that provides a private address space, within which code and data reside, along with an object space that retains the capabilities available within the task. Although the Fiasco (or L4Re) microkernel has some notion of all the tasks in the system, as well as all the threads, together with other kinds of objects, such global information is effectively private to the kernel, and “user space” programs merely deal with capabilities that reference specific objects. For such programs, there is no way to get some kind of universal list of tasks or threads, or to arbitrarily request control over any particular instances of them.

In systems with different characteristics to the ones we already know, we have to ask ourselves whether we want to reproduce legacy behaviour. To an extent, it might be desirable to have registers of resident processes and the ability to list the ones currently running in the system, introducing dedicated components to retain this information. Indeed, my process servers could quite easily enumerate and remember the details of processes they create, also providing an interface to query this register, maybe even an interface to control and terminate processes.

However, one must ask whether this is essential functionality or not. For now, the rudimentary shell-like environment I employ to test this work provides similar functionality to the job control features of the average Unix shell, remembering the processes created in this environment and offering control in a limited way over this particular section of the broader system.

And so the effort continues to try and build something a little different from, and perhaps a bit more flexible than, what we use today. Hopefully it is something that ends up being useful, too.

I seem to be spending too much time looking into obscure tales from computing history, but continuing an earlier tangent from a recent article, noting the performance of different computer systems at the end of the 1980s and the start of the 1990s, I found myself evaluating one of those Internet rumours that probably started to do the rounds about thirty years ago. We will get to that rumour – a tall tale, indeed – in a moment. But first, a chart that I posted in an earlier article:

As this nice chart indicates, comparing processor performance in computers from Acorn, Apple, Commodore and Compaq, different processor families bestowed a competitive advantage on particular systems at various points in time. For a while, Acorn’s ARM2 processor gave Acorn’s Archimedes range the edge over much more expensive systems using the Intel 80386, showcased in Compaq’s top-of-the-line models, as well as offerings from Apple and Commodore, these relying on Motorola’s 68000 family. One can, in fact, claim that a comparison between ARM-based systems and 80386-based systems would have been unfair to Acorn: more similarly priced systems from PC-compatible vendors would have used the much slower 80286, making the impact of the ARM2 even more remarkable.

Something might be said about the evolution of these processor families, what happened after 1993, and the introduction of later products. Such topics are difficult to address adequately for a number of reasons, principally the absence of appropriate benchmark results and the evolution of benchmarking to more accurately reflect system performance. Acorn never published SPEC benchmark figures, nor did ARM (at the time, at least), and any given benchmark as an approximation to “real-world” computing activities inevitably drifts away from being an accurate approximation as computer system architecture evolves.

However, in another chart I made to cover Acorn’s Unix-based RISC iX workstations, we can consider another range of competitors and quite a different situation. (This chart also shows off the nice labelling support in gnuplot that wasn’t possible with the currently disabled MediaWiki graph extension.)

Now, this chart only takes us from 1989 until 1992, which will not satisfy anyone wondering what happened next in the processor wars. But it shows the limits of Acorn’s ability to enter the lucrative Unix workstation market with a processor that was perceived to be rather fast in the world of personal computers. Acorn’s R140 used the same ARM2 processor introduced in the Archimedes range, but even at launch this workstation proved to be considerably slower than somewhat more expensive workstation models from Digital and Sun employing MIPS and SPARC processors respectively.

Fortunately for Acorn, adding a cache to the ARM2 (plus a few other things) to make the ARM3 unlocked a considerable boost in performance. Although the efficient utilisation of available memory bandwidth had apparently been a virtue for the ARM designers, coupling the processor to memory performance had put a severe limit on overall performance. Meanwhile, the designers of the MIPS and SPARC processor families had started out with a different perspective and had considered cache memory almost essential in the kind of computer architectures that would be using these processors.

Acorn didn’t make another Unix workstation after the R260, released in 1990, for reasons that could be explored in depth another time. One of them, however, was that ARM processor design had been spun out to a separate company, ARM Limited, and appeared to be stalling in terms of delivering performance improvements at the same rate as previously, or indeed at the same rate as other processor families. Acorn did introduce the ARM610 belatedly in 1994 in its Risc PC, which would have been more amenable to running Unix, but by then the company was arguably beginning the process of unravelling for another set of reasons to be explored another time.

So, That Tall Tale

It is against this backdrop of competitive considerations that I now bring you the tall tale to which I referred. Having been reminded of the Atari Transputer Workstation by a video about the Transputer – another fascinating topic and thus another rabbit hole to explore – I found myself investigating Atari’s other workstation product: a Unix workstation based on the Motorola 68030 known as the Atari TT030 or TT/X, augmenting the general Atari TT product with the Unix System V operating system.

On the chart above, a 68030-based system would sit at a similar performance level to Acorn’s R140, so ignoring aspirational sentiments about “high-end” performance and concentrating on a price of around $3000 (with a Unix licence probably adding to that figure), there were some hopes that Atari’s product would reach a broad audience:

As a UNIX platform, the affordable TT030 may leapfrog machines from IBM, Apple, NeXT, and Sun, as the best choice for mass installation of UNIX systems in these environments.

As it turned out, Atari released the TT without Unix in 1990 and only eventually shipped a Unix implementation in around 1992, discontinuing the endeavour not long afterwards. But the tall tale is not about Atari: it is about their rivals at Commodore and some bizarre claims that seem to have drifted around the Internet for thirty years.

Like Atari and Acorn, Commodore also had designs on the Unix workstation market. And like Atari, Commodore had a range of microcomputers, the Amiga series, based on the 68000 processor family. So, the natural progression for Commodore was to design a model of the Amiga to run Unix, eventually giving us the Amiga 3000UX, priced from around $5000, running an implementation of Unix System V Release 4 branded as “Amiga Unix”.

Reactions from the workstation market were initially enthusiastic but later somewhat tepid. Commodore’s product, although delivered in a much more timely fashion than Atari’s, will also have found itself sitting at a similar performance level to Acorn’s R140 but positioned chronologically amongst the group including Acorn’s much faster R260 and the 80486-based models. It goes without saying that Atari’s eventual product would have been surrounded by performance giants by the time customers could run Unix on it, demonstrating the need to bring products to market on time.

So what is this tall tale, then? Well, it revolves around this not entirely coherent remark, entered by some random person twenty-one years ago on the emerging resource known as Wikipedia:

The Amiga A3000UX model even got the attention of Sun Microsystems, but unfortunately Commodore did not jump at the A3000UX.

If you search the Web for this, including the Internet Archive, the most you will learn is that Sun Microsystems were supposedly interested in adopting the Amiga 3000UX as a low-cost workstation. But the basis of every report of this supposed interest always seems to involve “talk” about a “deal” and possibly “interest” from unspecified “people” at Sun Microsystems. And, of course, the lack of any eventual deal is often blamed on Commodore’s management and perennial villain of the Amiga scene…

There were talks of Sun Microsystems selling Amiga Unix machines (the prototype Amiga 3500) as a low-end Unix workstations under their brand, making Commodore their OEM manufacturer. This deal was let down by Commodore’s Mehdi Ali, not once but twice and finally Sun gave up their interest.

Of course, back in 2003, anything went on Wikipedia. People thought “I know this!” or “I heard something about this!”, clicked the edit link, and scrawled away, leaving people to tidy up the mess two decades later. So, I assume that this tall tale is just the usual enthusiast community phenomenon of believing that a favourite product could really have been a contender, that legitimacy could have been bestowed on their platform, and that their favourite company could have regained some of its faded glory. Similar things happened as Acorn went into decline, too.

Picking It All Apart

When such tales appeal to both intuition and even-handed consideration, they tend to retain a veneer of credibility: of being plausible and therefore possibly true. I cannot really say whether the tale is actually true, only that there is no credible evidence of it being true. However, it is still worth evaluating the details within such tales on their merits and determine whether the substance really sounds particularly likely at all.

So, why would Sun Microsystems be interested in a Commodore workstation product? Here, it helps to review Sun’s own product range during the 1980s, to note that Sun had based its original workstation on the Motorola 68000 and had eventually worked up the 68000 family to the 68030 in its Sun-3 products. Indeed, the final Sun-3 products were launched in 1989, not too long before the Amiga 3000UX came to market. But the crucial word in the previous sentence is “final”: Sun had adopted the SPARC processor family and had started introducing SPARC-based models two years previously. Like other workstation vendors, Sun had started to abandon Motorola’s processors, seeking better performance elsewhere.

A June 1989 review in Personal Workstation magazine is informative, featuring the 68030-based Sun 3/80 workstation alongside Sun’s SPARCstation 1. For diskless machines, the Sun 3/80 came in at around $6000 whereas the SPARCstation 1 came in at around $9000. For that extra $3000, the buyer was probably getting around four times the performance, and it was quite an incentive for Sun’s customers and developers to migrate to SPARC on that basis alone. But even for customers holding on to their older machines and wanting to augment their collection with some newer models, Sun was offering something not far off the “low-cost” price of an Amiga 3000UX with hardware that was probably more optimised for the role.

Sun will have supported customers using these Sun-3 models for as long as support for SunOS was available, eventually introducing Solaris which dropped support for the 68000 family architecture entirely. Just like other Unix hardware vendors, once a transition to various RISC architectures had been embarked upon, there was little enthusiasm for going back and retooling to support the Motorola architecture again. And, after years resisting, even Motorola was embracing RISC with its 88000 architecture, tempting companies like NeXT and Apple to consider trading up from the 68000 family: an adventure that deserves its own treatment, too.

So, under what circumstances would Sun have seriously considered adopting Commodore’s product? On the face of it, the potential compatibility sounds enticing, and Commodore will have undoubtedly asserted that they had experience at producing low-cost machines in volume, appealing to Sun’s estimate, expressed in the Personal Workstation review, that the customer base for a low-cost workstation would double for every $1000 drop in price. And surely Sun would have been eager to close the doors on manufacturing a product line that was going to be phased out sooner or later, so why not let Commodore keep making low-cost models to satisfy existing customers?

First of all, we might well doubt any claims to be able to produce workstations significantly cheaper than those already available. The Amiga 3000UX was, as noted, only $1000 or so cheaper than the Sun 3/80. Admittedly, it had a hard drive as standard, making the comparison slightly unfair, but then the Sun 3/80 was around already in 1989, meaning that to be fair to that product, we would need to see how far its pricing will have fallen by the time the Amiga 3000UX became available. Commodore certainly had experience in shipping large volumes of relatively inexpensive computers like the Amiga 500, but they were not shipping workstation-class machines in large quantities, and the eventual price of the Amiga 3000UX indicates that such arguments about volume do not automatically confer low cost onto more expensive products.

Even if we imagine that the Amiga 3000UX had been successfully cost-reduced and made more competitive, we then need to ask what benefits there would have been for the customer, for developers, and for Sun in selling such a product. It seems plausible to imagine customers with substantial investments in software that only ran on Sun’s older machines, who might have needed newer, compatible hardware to keep that software running. Perhaps, in such cases, the suppliers of such software were not interested or capable of porting the software to the SPARC processor family. Those customers might have kept buying machines to replace old ones or to increase the number of “seats” in their environment.

But then again, we could imagine that such customers, having multiple machines and presumably having them networked together, could have benefited from augmenting their old Motorola machines with new SPARC ones, potentially allowing the SPARC machines to run a suitable desktop environment and to use the old applications over the network. In such a scenario, the faster SPARC machines would have been far preferable as workstations, and with the emergence of the X Window System, a still lower-cost alternative would have been to acquire X terminals instead.

We might also question how many software developers would have been willing to abandon their users on an old architecture when it had been clear for some time that Sun would be transitioning to SPARC. Indeed, by producing versions of the same operating system for both architectures, one can argue that Sun was making it relatively straightforward for software vendors to prepare for future products and the eventual deprecation of their old products. Moreover, given the performance benefits of Sun’s newer hardware, developers might well have been eager to complete their own transition to SPARC and to entice customers to follow rapidly, if such enticement was even necessary.

Consequently, if there were customers stuck on Sun’s older hardware running applications that had been effectively abandoned, one could be left wondering what the scale of the commercial opportunity was in selling those customers more of the same. From a purely cynical perspective, given the idiosyncracies of Sun’s software platform from time to time, it is quite possible that such customers would have struggled to migrate to another 68000 family Unix platform. And even without such portability issues and with the chance of running binaries on a competing Unix, the departure of many workstation vendors to other architectures may have left relatively few appealing options. The most palatable outcome might have been to migrate to other applications instead and to then look at the hardware situation with fresh eyes.

And we keep needing to return to that matter of performance. A 68030-based machine was arguably unappealing, like 80386-based systems, clearing the bar for workstation computing but not by much. If the cost of such a machine could have been reduced to an absurdly low price point then one could have argued that it might have provided an accessible entry point for users into a vendor’s “ecosystem”. Indeed, I think that companies like Commodore and Acorn should have put Unix-like technology in their low-end products, harmonising them with higher-end products actually running Unix, and having their customers gradually migrate as more powerful computers became cheaper.

But for workstations running what one commentator called “wedding-cake configurations” of the X Window System, graphical user interface toolkits, and applications, processors like the 68030, 80386 and ARM2 were going to provide a disappointing experience whatever the price. Meanwhile, Sun’s existing workstations were a mature product with established peripherals and accessories. Any cost-reduced workstation would have been something distinct from those existing products, impaired in performance terms and yet unable to make use of things like graphics accelerators which might have made the experience tolerable.

That then raises the question of the availability of the 68040. Could Commodore have boosted the Amiga 3000UX with that processor, bringing it up to speed with the likes of the ARM3-based R260 and 80486-based products, along with the venerable MIPS R2000 and early SPARC processors? Here, we can certainly answer in the affirmative, but then we must ask what this would have done to the price. The 68040 was a new product, arriving during 1990, and although competitively priced relative to the SPARC and 80486, it was still quoted at around $800 per unit, featuring in Apple’s Macintosh range in models that initially, in 1991, cost over $5000. Such a cost increase would have made it hard to drive down the system price.

In the chart above, the HP 9000/425t represents possibly the peak of 68040 workstation performance – “a formidable entry-level system” – costing upwards of $9000. But as workstation performance progressed, represented by new generations of DECstations and SPARCstations, the 68040 stalled, unable to be clocked significantly faster or otherwise see its performance scaled up. Prominent users such as Apple jumped ship and adopted PowerPC along with Motorola themselves! Motorola returned to the architecture after abandoning further development of the 88000 architecture, delivering the 68060 before finally consigning the architecture to the embedded realm.

In the end, even if a competitively priced and competitively performing workstation had been deliverable by Commodore, would it have been in Sun’s interests to sell it? Compatibility with older software might have demanded the continued development of SunOS and the extension of support for older software technologies. SunOS might have needed porting to Commodore’s hardware, or if Sun were content to allow Commodore to add any necessary provision to its own Unix implementation, then porting of those special Sun technologies would have been required. One can question whether the customer experience would have been satisfactory in either case. And for Sun, the burden of prolonging the lifespan of products that were no longer the focus of the company might have made the exercise rather unattractive.

Companies can always choose for themselves how much support they might extend to their different ranges of products. Hewlett-Packard maintained several lines of workstation products and continued to maintain a line of 68030 and 68040 workstations even after introducing their own PA-RISC processor architecture. After acquiring Apollo Computer, who had also begun to transition to their own RISC architecture from the 68000 family, HP arguably had an obligation to Apollo’s customers and thus renewed their commitment to the Motorola architecture, particularly since Apollo’s own RISC architecture, PRISM, was shelved by HP in favour of PA-RISC.

It is perhaps in the adoption of Sun technology that we might establish the essence of this tale. Amiga Unix was provided with Sun’s OPEN LOOK graphical user interface, and this might have given people reason to believe that there was some kind of deeper alliance. In fact, the alliance was really between Sun and AT&T, attempting to define Unix standards and enlisting the support of Unix suppliers. In seeking to adhere most closely to what could be regarded as traditional Unix – that defined by its originator, AT&T – Commodore may well have been picking technologies that also happened to be developed by Sun.

This tale rests on the assumption that Sun was not able to drive down the prices of its own workstations and that Commodore was needed to lead the way. Yet workstation prices were already being driven down by competition. Already by May 1990, Sun had announced the diskless SPARCstation SPC at the magic $5000 price point, although its lowest-cost colour workstation was reportedly the SPARCstation IPC at a much more substantial $10000. Nevertheless, its competitors were quite able to demonstrate colour workstations at reasonable prices, and eventually Sun followed their lead. Meanwhile, the Amiga 3000UX cost almost $8000 when coupled with a colour monitor.

With such talk of commodity hardware, it must not be forgotten that Sun was not without other options. For example, the company had already delivered SunOS on the Sun386i workstation in 1988. Although rather expensive, costing $10000, and not exactly a generic PC clone, it did support PC architecture standards. This arguably showed the way if the company were to target a genuine commodity hardware platform, and eventually Sun followed this path when making its Solaris operating system available for the Intel x86 architecture. But had Sun had a desperate urge to target commodity hardware back in 1990, partnering with a PC clone manufacturer would have been a more viable option than repurposing an Amiga model. That clone manufacturer could have been Commodore, too, but other choices would have been more convincing.

Conclusions and Reflections

What can we make of all of this? An idle assertion with a veneer of plausibility and a hint of glory denied through the notoriously poor business practices of the usual suspects. Well, we can obviously see that nothing is ever as simple as it might seem, particularly if we indulge every last argument and pursue every last avenue of consideration. And yet, the matter of Commodore making a Unix workstation and Sun Microsystems being “interested in rebadging the A3000UX” might be as simple as imagining a rather short meeting where Commodore representatives present this opportunity and Sun’s representatives firmly but politely respond that the door has been closed on a product range not long for retirement. Thanks but no thanks. The industry has moved on. Did you not get that memo?

Given that there is the essence of a good story in all of this, I consulted what might be the first port of call for Commodore stories: David Pleasance’s book, “Commodore The Inside Story”. Sadly, I can find no trace of any such interaction, with Unix references relating to a much earlier era and Commodore’s Z8000-based Unix machine, the unreleased Commodore 900. Yet, had such a bungled deal occurred, I am fairly sure that this book would lay out the fiasco in plenty of detail. Even Dave Haynie’s chapter, which covers development of the Amiga 3000 and subsequent projects, fails to mention any such dealings. Perhaps the catalogue of mishaps at Commodore is so extensive that a lucrative agreement with one of the most prominent corporations in 1990s computing does not merit a mention.

Interestingly, the idea of a low-cost but relatively low-performance 68030-based workstation from a major Unix workstation vendor did arrive in 1989 in the form of the Apollo DN2500, costing $4000, from Hewlett-Packard. Later on, Commodore would apparently collaborate with HP on chipset development, with this being curtailed by Commodore’s bankruptcy. Commodore were finally moving off the 68000 family architecture themselves, all rather too late to turn their fortunes around. Did Sun need a competitive 68040-based workstation? Although HP’s 9000/425 range was amongst the top sellers, Sun was doing nicely enough with its SPARC-based products, shipping over twice as many workstations as HP.

While I consider this tall tale to be nothing more than folklore, like the reminiscences of football supporters whose team always had a shot at promotion to the bigger league every season, “not once but twice” has a specificity that either suggests a kernel of truth or is a clever embellishment to sustain a group’s collective belief in something that never was. Should anyone know the real story, please point us to the documentation. Or, if there never was any paper trail but you happened to be there, please write it up and let us all know. But please don’t just go onto Wikipedia and scrawl it in the tradition of “I know this!”

For the record, I did look around to see if anyone recorded such corporate interactions on Sun’s side. That yielded no evidence, but I did find something else that was rather intriguing: hints that Sun may have been advised to try and acquire Acorn or ARM. Nothing came from that, of course, but at least this is documentation of an interaction in the corporate world. Of stories about something that never happened, it might also be a more interesting one than the Commodore workstation that Sun never got to rebadge.

Update: I did find a mention of Sun Microsystems and Unix International featuring the Amiga 3000UX on their exhibition stands at the Uniforum conference in early 1991. As noted above, Sun had an interest in promoting adoption of OPEN LOOK, and Unix International – the Sun/AT&T initiative to define Unix standards – had an interest in promoting System V Release 4 and, to an extent, OPEN LOOK. So, while the model may have “even got the attention of Sun Microsystems”, it was probably just a nice way of demonstrating vendor endorsement of Sun’s technology from a vendor who admitted that what it could offer was not “competitive with Sun” and what it had to offer.