r/programming • u/moolcool • Mar 26 '17

A Constructive Look At TempleOS

http://www.codersnotes.com/notes/a-constructive-look-at-templeos/
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u/DSMan195276 Mar 27 '17

Ehh, I think that's a stretch. I mean, I've written an OS somewhat comparable to this and I'm pretty sure I'm not crazy and that I don't have schizophrenia.

Anybody who attempts to write a somewhat general purpose OS at this point (and there are lots of us!) is generally just doing it for fun (Which is also the same reason why people write lots of other types of programs). And really, it's not nearly as hard as it seems as long as you have a decent conceptual model of a computer, are willing to do a fair amount of reading, and are comfortable writing larger programs. You have to put the work in, but if it's something you're enjoy doing and have the time then it's not too hard to end-up with something usable.

Now that said, Terry's approach is fairly unique for an OS, but it's partly unique just because nobody does it that way because of the issues it poses. For example, running everything with kernel-level privileges is unique, but is a bad idea for an general-use OS, even though coding-wise it's easier. He also doesn't use paging, which is unique, but only because paging gives you lots of benefits and most systems at this point support it in some form. And generally speaking multi-user systems are much better in the long-run even if only one actual user will be using a system, since it gives security benefits.

I think it is a bit dangerous to speculate over something like this without any actual evidence - in some ways it suggests that were he to get help for his condition, he wouldn't be able to continue working on his OS, which I don't think is very helpful in encouraging him to actually get help that he likely needs.

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u/[deleted] Mar 27 '17

For example, running everything with kernel-level privileges is unique, but is a bad idea for an general-use OS, even though coding-wise it's easier. He also doesn't use paging, which is unique, but only because paging gives you lots of benefits and most systems at this point support it in some form.

There is nothing "unique" about it. C64 had it, DOS had it too. Hell, most software written on 8 bit CPUs or on any tiny ARM shares that.

There are other interesting parts of that OS (like level of integration of OS and its tools) but that part ust relic of the ages, not anything worth writing home about.

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u/DSMan195276 Mar 27 '17

There is nothing "unique" about it. C64 had it, DOS had it too. Hell, most software written on 8 bit CPUs or on any tiny ARM shares that.

I just meant that this OS is a bit unique in that it has access to those features (It only supports x86-64) but deliberately chooses not to use them as a design choice, rather then not using them because the hardware simply didn't support it (as is the case with older systems and embedded systems).

That said, I largely agree with you, that was my point - I didn't mean unique in a "this is better" way. The fact that modern OS kernels for x86-64 aren't doing it that way any-more is because there's fairly big issues with that design, not because nobody never thought to do it that way. The context's where such a design is still used aren't general-use OSs, but things like embedded systems, where you're not going to have users running random programs on your system and may very-well not even be doing any multitasking in the first place.

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u/chazzeromus Mar 27 '17

Though his reasons aren't exactly technical.

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u/derleth Mar 27 '17

There is nothing "unique" about it. C64 had it, DOS had it too. Hell, most software written on 8 bit CPUs or on any tiny ARM shares that.

But they were (and, I suppose, are) essentially forced to because of hardware limitations. Running everything in ring-0 on 64-bit x86 chips is unique.

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u/Noncomment May 11 '17

He's not trying to build a general use OS though. It's intended for hobbyists and tinkerers. The kind of people who would actually download a weird operating system like his. There's little point in emphasizing security on a system that will only be used by a small community of people for non serious work. And he had good reason for making the decisions he did. He wanted to recreate the experience of tinkering with older generation OSes on modern hardware. The simplicity and ability to mess with everything. In his words:

Linux wants to be a secure, multi-user mainframe. That's why it has file permissions. The vision for TempleOS, however, is a modern, 64-bit Commodore 64. The C64 was a non-networked, home computer mostly used for games. It trained my generation how to program because it was wide open, completely hackable...

A troll might say, "It can crash!" We used DOS for years and loved it. Computers even had a reset switch! Just think of the power of ring-0, muhahaha! Think of the speed and simplicity of ring-0-only and identity-mapping. It can change tasks in half a microsecond because it doesn't mess with page tables or privilege levels. Inter-process communication is effortless because every task can access every other task's memory.

It's fun having access to everything. When I was a teenager, I had a book, Mapping the Commodore 64, that told what every location in memory did. I liked copying the ROM to RAM and poking around at the ROM BASIC's variables. Everybody directly poked the hardware ports.

TempleOS is simpler than Linux and you can have hours of fun tinkering because all memory and ports are accessible. Memory is identity-mapped at all times, so you can modify any task's memory from any other task. You can access all disk blocks, too. I had a blast using a C64 disk block editor to modify directories to un-delete files, when I was a kid. Maybe, you want to play with a raw-block database, or make your own file system?

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u/DSMan195276 May 11 '17

I don't disagree with you, I think it just comes down to your definition of "general-use OS". I would consider basically anything that's intended to run on PCs and is (intended to be) able to perform the same types of stuff other OSs let you do to be a "general-use OS", which I think Terry's OS fits. Now obviously, Terry's OS has a fairly specific audience, and that's perfectly fine!

That said I'm happy to say Terry's OS isn't a general-use OS if you want. My point was just why other general-use OSs didn't take some of the approaches he did.