4 ms·

I don't know why, but I absolute adore these stories of "Why does this obscure thing operate in the obscure way it does?" answered by the primary source. They'r

I don't know why, but I absolute adore these stories of "Why does this obscure thing operate in the obscure way it does?" answered by the primary source. They're fascinating glimpses into the never-ending sea of trade-offs that is professional engineering!

BorisMelnik 12y ago
same, here, esp for features that have been with us since DOS 1.x etc very nostalgic
rbanffy 12y ago
Indeed. The comedic value of the IBM PC architecture and its myriad of cautionary tales cannot be overemphasised. From the keyboard controller controlling a short to the A20 line to the rather questionable choice of using a programmable timer to generate audio (BTW, what was used in the cassette port?) and the 6845 sync frequencies that would ruin (if not set fire to) an MDA monitor, all the way to write-only EGA registers and the TSRs that were needed to keep track of which video mode the screen was on, the list and its hilarity, is enormous. I assume the IBM engineers who came up with these ideas had a lot of fun.
- raverbashing 12y ago
  > I assume the IBM engineers who came up with these ideas had a lot of fun. IBM is incompatible with fun It was about cost mainly and backwards compatibility
  - rbanffy 12y ago
    > IBM is incompatible with fun Maybe officially, but it's hard not to appreciate engineers getting away making the most idiotic, borderline surreal, technical decisions for multiple generations of a machine architecture. The PC must have been the most hated piece of hardware ever to be designed within IBM and the outlet of countless corporate-induced frustrations.
    - jandrese 12y ago
      Most things that look crazy from the outside probably had very good reasons for existing. There's usual some weird technical quirk that made it work the way it does, and working around the problem (or doing it right) would have required a few thousand more gates or a couple more pins which would have been expensive. Making something correct with no regard for cost is relatively easy. Making something that works at all but costs less than $5 in bulk can be a lot more difficult.
    - cbd1984 12y ago
      I cannot well repeat how there I entered, So full was I of slumber at the moment In which I had abandoned the true way. The Divine Comedy/Inferno/Canto I, by Dante Alighieri, Translated by Henry Wadsworth Longfellow http://genius.com/Dante-alighieri-inferno-canto-1-annotated/ http://genius.com/Dante-alighieri-inferno-canto-1-annotated/ My point is, it's easy to get into this kind of weird design world, if you just do the quickest thing at every step, with no ability to think about how the big picture is going to look. I'm sure nobody wanted to make a weird architecture, because they're harder to extend and harder to write software for, but if you always have the deadlines breathing down your neck, don't be surprised if you end up in a scary forest indeed.
cbd1984 12y ago
Raymond Chen does a lot of this kind of thing for MS-related stuff, especially older Windows versions: http://blogs.msdn.com/b/oldnewthing/ http://blogs.msdn.com/b/oldnewthing/

BorisMelnik 12y ago

same, here, esp for features that have been with us since DOS 1.x etc very nostalgic

rbanffy 12y ago

Indeed. The comedic value of the IBM PC architecture and its myriad of cautionary tales cannot be overemphasised. From the keyboard controller controlling a short to the A20 line to the rather questionable choice of using a programmable timer to generate audio (BTW, what was used in the cassette port?) and the 6845 sync frequencies that would ruin (if not set fire to) an MDA monitor, all the way to write-only EGA registers and the TSRs that were needed to keep track of which video mode the screen was on, the list and its hilarity, is enormous. I assume the IBM engineers who came up with these ideas had a lot of fun.

raverbashing 12y ago
> I assume the IBM engineers who came up with these ideas had a lot of fun. IBM is incompatible with fun It was about cost mainly and backwards compatibility
- rbanffy 12y ago
  > IBM is incompatible with fun Maybe officially, but it's hard not to appreciate engineers getting away making the most idiotic, borderline surreal, technical decisions for multiple generations of a machine architecture. The PC must have been the most hated piece of hardware ever to be designed within IBM and the outlet of countless corporate-induced frustrations.
  - jandrese 12y ago
    Most things that look crazy from the outside probably had very good reasons for existing. There's usual some weird technical quirk that made it work the way it does, and working around the problem (or doing it right) would have required a few thousand more gates or a couple more pins which would have been expensive. Making something correct with no regard for cost is relatively easy. Making something that works at all but costs less than $5 in bulk can be a lot more difficult.
  - cbd1984 12y ago
    I cannot well repeat how there I entered, So full was I of slumber at the moment In which I had abandoned the true way. The Divine Comedy/Inferno/Canto I, by Dante Alighieri, Translated by Henry Wadsworth Longfellow http://genius.com/Dante-alighieri-inferno-canto-1-annotated/ http://genius.com/Dante-alighieri-inferno-canto-1-annotated/ My point is, it's easy to get into this kind of weird design world, if you just do the quickest thing at every step, with no ability to think about how the big picture is going to look. I'm sure nobody wanted to make a weird architecture, because they're harder to extend and harder to write software for, but if you always have the deadlines breathing down your neck, don't be surprised if you end up in a scary forest indeed.

cbd1984 12y ago

Raymond Chen does a lot of this kind of thing for MS-related stuff, especially older Windows versions: http://blogs.msdn.com/b/oldnewthing/ http://blogs.msdn.com/b/oldnewthing/