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> Isn't the BIOS supposed to be the hardware abstracting layer we run our programs directly on? Yes. The problem with this idea is that the BIOS fell prey to a

by derleth 13y ago

> Isn't the BIOS supposed to be the hardware abstracting layer we run our programs directly on? Yes. The problem with this idea is that the BIOS fell prey to a classic negative feedback loop: It wasn't extremely efficient to begin with, and in 16-bit x86 programs can bypass it entirely and go directly to the hardware, so they did. This meant hardware interfaces became more standardized (to a point), to make specific pieces of hardware more attractive to buyers who wanted to run the widest possible variety of application software, and the BIOS was relatively neglected. This cycle continued until the BIOS had essentially code-rotted into unusability, being able to boot Windows and not much else. The final nail in the coffin was when 32-bit x86 chips came out and the BIOS remained 16-bit real mode: Even though protected mode could have saved the BIOS, by making it impossible for application software to go directly to the hardware, the fact the BIOS never jumped to 32-bit code meant not even OSes can really use it. So now the BIOS can run a POST and load a bootloader that actually knows how to load a modern OS. That's pretty much it.

rbanffy 13y ago
> It wasn't extremely efficient to begin with Actually, it was quite ridiculous. Printing text to the screen on a 4.77 IBM PC felt like using a serial terminal at about 19200 bps. My 1 MHz Apple II would appear much faster just because it could output text to the screen more efficiently (to be fair, putting a symbol on a CGA screen is a two-byte affair - one for the symbol, one for attributes, but, still, for a supposedly much more advanced machine, it was horrible).
- derleth 13y ago
  > to be fair, putting a symbol on a CGA screen is a two-byte affair - one for the symbol, one for attributes Text-heavy stuff was supposed to be done using MDA graphics cards, which were praised at their introduction for allowing large amounts of readable text, especially on IBM's own monitors. I'm sure a lot of business users running 3270 terminal emulators and word processors got a lot of good use out of MDA, but the fact it was, as its name stated, monochrome pretty much killed it in the home market. Anyway, the IBM PC was very definitely built to a price point and a release date; it was also built to avoid cannibalizing any of IBM's pre-existing product line, which explains why Compaq, not IBM, would come out with the first PC built around the 80386. It was fairly impressive compared to S-100 bus computers running CP/M but the Apple II crowd would have been forgiven for not being bowled over.

by derleth 13y ago

rbanffy 13y ago

> It wasn't extremely efficient to begin with Actually, it was quite ridiculous. Printing text to the screen on a 4.77 IBM PC felt like using a serial terminal at about 19200 bps. My 1 MHz Apple II would appear much faster just because it could output text to the screen more efficiently (to be fair, putting a symbol on a CGA screen is a two-byte affair - one for the symbol, one for attributes, but, still, for a supposedly much more advanced machine, it was horrible).

derleth 13y ago
> to be fair, putting a symbol on a CGA screen is a two-byte affair - one for the symbol, one for attributes Text-heavy stuff was supposed to be done using MDA graphics cards, which were praised at their introduction for allowing large amounts of readable text, especially on IBM's own monitors. I'm sure a lot of business users running 3270 terminal emulators and word processors got a lot of good use out of MDA, but the fact it was, as its name stated, monochrome pretty much killed it in the home market. Anyway, the IBM PC was very definitely built to a price point and a release date; it was also built to avoid cannibalizing any of IBM's pre-existing product line, which explains why Compaq, not IBM, would come out with the first PC built around the 80386. It was fairly impressive compared to S-100 bus computers running CP/M but the Apple II crowd would have been forgiven for not being bowled over.