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By 1989 RISC OS was awesome, but by 1995 it lacked the same features as other famous OSs (I will not name the other OS to avoid a flame war). RISC OS used coop

By 1989 RISC OS was awesome, but by 1995 it lacked the same features as other famous OSs (I will not name the other OS to avoid a flame war). RISC OS used cooperative multitasking and it lacked virtual memory protection. By 1995 linux or BSD were better platforms. MS released Windows 95 and preemptive multitasking arrived to millions of homes. I still have a 2002 PACE based RISC OS in the basement. It boots with bootp+NFS. It was part of a kiosk that was replaced by a BSD box. No booting or runtime issues anymore. We even designed a serial watchdog to ensure a reboot if the STB hanged, because riscos hanged even booting. No issues with the BSD. In my humble opinion by the mid 1990s preemptive multitasking and memory protection was mandatory in a general purpose OS and RISC OS lacked it.

zbuf 6y ago
Someone with a more detailed knowledge of RISC OS may correct me, but to the best of my knowledge there _was_ virtual memory protection between applications (the article carefully says "worthwhile memory protection") Virtual memory was undermined by large portions of the OS being implemented as, effectively kernel modules. That is because this was the provided mechanism for 'shared' libraries; there's no dynamic linker, as such, just syscalls. So perhaps it can be attributed more not to lack of virtual memory, but lack of a mechanism for shared libraries (and IPC) It is certainly true that as features from multi-user systems began to make an appearance on PC desktops, RISC OS starts to get left behind in this area. But also recall that wasn't the focus (for a self-selected user base, of course.) An OS geared to productivity, with features like consistent widgets (and style guide), drag and drop between apps, consistent filesystem interaction throughout and standardised anti-aliased font and vector graphic rendering as part of the OS. It's 2020 and it doesn't feel like any of the OSes I use today have anything like the same cohesion (let alone web apps) They were, however, the early victories of RISC OS. It does look like in the latter years 'easy' stuff was worked on; things like new window decor and textured backgrounds; perhaps diverting attention (either the RISC OS developers, or users) from the core. I'm rather interested what Acorn's take was on the porting of NetBSD to Acorn hardware (which I first saw at a show in about 1995). With the benefit of hindsight, perhaps RISC OS could have been layered atop of this. A BSD kernel with a RISC OS syscall interface, windowing system and BASIC interpreter to provide compatibility for the wealth of existing software, and a transition to a 'modern' OS. Was this considered at the time? Was anyone at Acorn paying attention to BSD? Was there enough people-power to make it feasible? Was Acorn already in trouble by then? The world could have been a very different place.
- fanf2 6y ago
  Multitasking in RISC OS was based on swapping the page tables for the application part of the address space starting at 0x8000. Applications were not relocatable, so memory protection was more like a side effect of the address space layout than a deliberate security feature. There was some memory protection to make pages read-only for user code, notably page zero (to trap null pointer dereferences, and to protect the interrupt vectors) but my memory is that the system heap (containing the OS modules) was either directly writable from userspace, or it was trivial to make a system call to get write access.
- laurencerowe 6y ago
  > Was anyone at Acorn paying attention to BSD? Acorn sold BSD derived RISC iX workstations (the hardware was just rebadged Archimedes) from 1988. https://en.wikipedia.org/wiki/RISC_iX https://en.wikipedia.org/wiki/RISC_iX
  - flir 6y ago
    Had one of those at my VIth Form - think it was an ex-display model Acorn had demo'd at a trade show (suspect it was an A680, it definitely had SCSI). Can't underestimate the lure of that mysterious "real" OS it would boot into. My first exposure to 'nix.
    - danellis 6y ago
      My first exposure to Unix was RiscBSD, which was netbsd/arm26 running on a RISC PC. Installed from a pile of floppies downloaded at school. Eventually I got an old Elonex 386 that I could install Slackware on, and with a bit of coax I had a 10base2 home network and was being amazed at the concept of running X clients remotely.
  - jacquesm 6y ago
    They also made a full UNIX workstation called the Unicorn.
    - 6y ago
ris 6y ago
This. I think the author is making the mistake of comparing it with what I would call "new world" OSs. Very broadly I would categorize most OSs of the 90s into old-world and new-world, common traits of the old-world being: - Minimal or no memory protection - Minimal or no real user separation - Usually desktop-focussed - Cooperative multitasking at best - Heavily reliant on assembly and hardware specifics with vendors one by one realizing they had to make a big compatibility-breaking leap to introduce the features now expected for a desktop OS. (cue tens of replies pointing out exceptions, sure) As an old-world OS, in 1991, I do still think that RISC OS did a pretty good job from a user's perspective. My memories are of it being fast, attractive (anti-aliased fonts?!) and intuitive (often ingenious). With an extremely powerful inbuilt BASIC implementation, to add. The more I've looked in to RISC OS more recently, the more I've realized how many compromises had to be made to achieve this, and I'm sure they were running out of headroom to evolve it towards a new-world OS. But really this was true for most old-world OSs I can think of. (again, cue exceptions)
- NikkiA 6y ago
  I think part of it is that RiscOS had some new-world features, and like the other 'straddling' OSs of the early 90s (OS/2, Desqview/GEM) maybe felt they didn't need to make a big leap to adapt to changes in user expectation, and failed because they had a klunkiness as a result.
  - pmyteh 6y ago
    My suspicion is that, by the time it became obvious that such things would be essential (maybe 1994 onwards) then the writing was already on the wall. RISC OS was a relatively niche system even in the late 1980s, and it was clear to even to those of us who were enthusiasts as early as 1993 or so that it was going to be left behind. Acorn had weak sales as PCs became standard in schools (its previous strength), the OS was tightly tied to the existing hardware, and there was no money to do whatever radical overhauls that would be necessary to make the 'big leap' for a small market. I used a RISC OS machine as my primary computer all the way through to 2004, but it was seven or so years past its best by then, and probably twelve since RISC OS was even a potential world-beater.
II2II 6y ago
Keep in mind, most people were using operating systems that were on par with RISC OS in 1995. Most homes and offices still used DOS or Windows 3.1, Windows 95 was just introduced, Mac OS would not see preemptive multitasking or memory protection for another five years, the uptake of OS/2 and Windows NT was rather low, Commodore was bankrupt, Atari was in serious trouble, BeOS was still in development, and NeXTSTEP was targeted at high end workstations.

zbuf 6y ago

Someone with a more detailed knowledge of RISC OS may correct me, but to the best of my knowledge there _was_ virtual memory protection between applications (the article carefully says "worthwhile memory protection") Virtual memory was undermined by large portions of the OS being implemented as, effectively kernel modules. That is because this was the provided mechanism for 'shared' libraries; there's no dynamic linker, as such, just syscalls. So perhaps it can be attributed more not to lack of virtual memory, but lack of a mechanism for shared libraries (and IPC) It is certainly true that as features from multi-user systems began to make an appearance on PC desktops, RISC OS starts to get left behind in this area. But also recall that wasn't the focus (for a self-selected user base, of course.) An OS geared to productivity, with features like consistent widgets (and style guide), drag and drop between apps, consistent filesystem interaction throughout and standardised anti-aliased font and vector graphic rendering as part of the OS. It's 2020 and it doesn't feel like any of the OSes I use today have anything like the same cohesion (let alone web apps) They were, however, the early victories of RISC OS. It does look like in the latter years 'easy' stuff was worked on; things like new window decor and textured backgrounds; perhaps diverting attention (either the RISC OS developers, or users) from the core. I'm rather interested what Acorn's take was on the porting of NetBSD to Acorn hardware (which I first saw at a show in about 1995). With the benefit of hindsight, perhaps RISC OS could have been layered atop of this. A BSD kernel with a RISC OS syscall interface, windowing system and BASIC interpreter to provide compatibility for the wealth of existing software, and a transition to a 'modern' OS. Was this considered at the time? Was anyone at Acorn paying attention to BSD? Was there enough people-power to make it feasible? Was Acorn already in trouble by then? The world could have been a very different place.

fanf2 6y ago
Multitasking in RISC OS was based on swapping the page tables for the application part of the address space starting at 0x8000. Applications were not relocatable, so memory protection was more like a side effect of the address space layout than a deliberate security feature. There was some memory protection to make pages read-only for user code, notably page zero (to trap null pointer dereferences, and to protect the interrupt vectors) but my memory is that the system heap (containing the OS modules) was either directly writable from userspace, or it was trivial to make a system call to get write access.
laurencerowe 6y ago
> Was anyone at Acorn paying attention to BSD? Acorn sold BSD derived RISC iX workstations (the hardware was just rebadged Archimedes) from 1988. https://en.wikipedia.org/wiki/RISC_iX https://en.wikipedia.org/wiki/RISC_iX
- flir 6y ago
  Had one of those at my VIth Form - think it was an ex-display model Acorn had demo'd at a trade show (suspect it was an A680, it definitely had SCSI). Can't underestimate the lure of that mysterious "real" OS it would boot into. My first exposure to 'nix.
  - danellis 6y ago
    My first exposure to Unix was RiscBSD, which was netbsd/arm26 running on a RISC PC. Installed from a pile of floppies downloaded at school. Eventually I got an old Elonex 386 that I could install Slackware on, and with a bit of coax I had a 10base2 home network and was being amazed at the concept of running X clients remotely.
- jacquesm 6y ago
  They also made a full UNIX workstation called the Unicorn.
  - 6y ago

ris 6y ago

This. I think the author is making the mistake of comparing it with what I would call "new world" OSs. Very broadly I would categorize most OSs of the 90s into old-world and new-world, common traits of the old-world being: - Minimal or no memory protection - Minimal or no real user separation - Usually desktop-focussed - Cooperative multitasking at best - Heavily reliant on assembly and hardware specifics with vendors one by one realizing they had to make a big compatibility-breaking leap to introduce the features now expected for a desktop OS. (cue tens of replies pointing out exceptions, sure) As an old-world OS, in 1991, I do still think that RISC OS did a pretty good job from a user's perspective. My memories are of it being fast, attractive (anti-aliased fonts?!) and intuitive (often ingenious). With an extremely powerful inbuilt BASIC implementation, to add. The more I've looked in to RISC OS more recently, the more I've realized how many compromises had to be made to achieve this, and I'm sure they were running out of headroom to evolve it towards a new-world OS. But really this was true for most old-world OSs I can think of. (again, cue exceptions)

NikkiA 6y ago
I think part of it is that RiscOS had some new-world features, and like the other 'straddling' OSs of the early 90s (OS/2, Desqview/GEM) maybe felt they didn't need to make a big leap to adapt to changes in user expectation, and failed because they had a klunkiness as a result.
- pmyteh 6y ago
  My suspicion is that, by the time it became obvious that such things would be essential (maybe 1994 onwards) then the writing was already on the wall. RISC OS was a relatively niche system even in the late 1980s, and it was clear to even to those of us who were enthusiasts as early as 1993 or so that it was going to be left behind. Acorn had weak sales as PCs became standard in schools (its previous strength), the OS was tightly tied to the existing hardware, and there was no money to do whatever radical overhauls that would be necessary to make the 'big leap' for a small market. I used a RISC OS machine as my primary computer all the way through to 2004, but it was seven or so years past its best by then, and probably twelve since RISC OS was even a potential world-beater.

II2II 6y ago

Keep in mind, most people were using operating systems that were on par with RISC OS in 1995. Most homes and offices still used DOS or Windows 3.1, Windows 95 was just introduced, Mac OS would not see preemptive multitasking or memory protection for another five years, the uptake of OS/2 and Windows NT was rather low, Commodore was bankrupt, Atari was in serious trouble, BeOS was still in development, and NeXTSTEP was targeted at high end workstations.