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RISC OS, the operating system that ran on the first few generations of ARM CPUs in the 1980s and early 1990s, was stored on ROM chips. It booted in a few secon
by Symbiote 3y ago
RISC OS, the operating system that ran on the first few generations of ARM CPUs in the 1980s and early 1990s, was stored on ROM chips. It booted in a few seconds, to a real OS with a GUI etc.
https://youtu.be/5M6OIOIND-0?t=1278 https://youtu.be/5M6OIOIND-0?t=1278 — I think about 12 seconds, or which 3-4 is waiting for two hard drives to spin up.
- bluGill 3y agoWhich is great and fast - until you want/need to upgrade the OS. Security hole, too bad, that is baked into ROM and can't be fixed...
- Symbiote 3y agoRISC OS could selectively replace parts of the ROM (in RAM) with new code/data, for upgrades, new device drivers and so on. (I think some viruses loaded themselves with this mechanism. And virus checkers.) https://www.riscosopen.org/wiki/documentation/show/File%20formats:%20Relocatable%20Module https://www.riscosopen.org/wiki/documentation/show/File%20fo...
- bluGill 3y agoSure, but everytime you need to do that boot time goes down and so what was the point?
- Symbiote 3y agoIn practise I don't remember this being a big deal. At some point I remember helping my dad upgrade us from RISC OS 3.something to 3.11, by replacing the ROM chips, but patches to the OS loaded into RAM were unusual. The OS in ROM was 2MiB, and looking at some module files intended for potential loading at boot time I have in an emulator, they are around 5-40kiB. The computers typically had 2 or 4MiB RAM, so there isn't space to replace a significant amount of the OS anyway. (1MiB or 8MiB was possible, but unusual.)
- cmrdporcupine 3y agoWow, that's a large ROM. Even in their latest, 68030 based models, Atari never shipped a ROM bigger than I think 512kB (in the TT). If you wanted the full multitasking modern version of the OS (MultiTOS), you loaded parts of it from disk. Or ran SysV Unix (or NetBSD or Linux, later). Then again, binary sizes would be smaller on a CISC 68k machine I'd expect.
- Symbiote 3y agoSome of it's shown later in the long video I posted if you want to look, but the ROM includes the multitasking OS, GUI, BASIC interpreter, text editor, graphics editor, vector drawing editor, calculator, clock/alarm clock, font manager and four fonts, network stack (though not IP), RAM filing system, audio support.
- cmrdporcupine 3y agoAtari ST also booted from ROM. But it also expected a floppy disk to be in the drive, to check for auto boot programs, etc. So that slowed the boot. If there was no floppy, it would hang for a while waiting for one, even. Poor choice.
- Symbiote 3y agoIn RISC OS that was optional. There was a setting[1] in NVRAM which set whether or not to look for a boot device, and what that boot device was (floppy disc, hard disc, network). I don't remember what happened if you configured it to look for extra boot files on a floppy disc, but the drive was empty. I think it would give up very quickly (1-2 seconds), as it was a normal way to load a program on the earlier BBC computers — insert the program disc, which would be bootable, and press the key combination (Shift+Break) to reset. "Podules" (expansion cards) could also map extra modules into the OS from their own ROM, usually the required device drivers for the card. [1] https://www.riscosopen.org/wiki/documentation/show/*Configure%20Boot https://www.riscosopen.org/wiki/documentation/show/*Configur...
- cmrdporcupine 3y agoOn the ST you could hit ESC to make it skip the floppy check, I believe.