Mastodon bot hn100@social.lansky.name reposts the link
3 Yesterday 1:55 AM · 1d ago · 1 post · 1 source · development 3 of 3
A second automated Mastodon account, which republishes Hacker News items, posted the same Quora link and HN discussion URL roughly ten hours later.
Alan Kay Computer scientist, author of the Quora answermidnightfish Hacker News submitter
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What people said 7 voices · verbatim
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Somewhat tangential, I've watched a bunch of videos on YouTube from @deramp5113 about the Altair 8800 and other early microcomputers, which feature a similar set of front panel switches for dialing in your initial program. One thing that's interesting to me, as someone who learned computing in the late 90s, is how much is expressed in octal…
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The EDSAC's "boot ROM" consisted of a bank of large electro-meachanical "uniselector" rotary switches, hardwired to contain the 31 instructions ("initial orders") of the tape loader.Subsequent computers could have followed this "electro-mechanical ROM" approach, but I suppose it was rather bulky and inconvenient to change.You can see what the…
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> It seems a little strange that more advanced later machines like the original PDP-11 from 1970, couldn't "autostart" from ROM like that.Because the PDPs had magnetic core memory, so the bootloader, once toggled in, stayed in memory. The OS took care not to overwrite it.And in normal operation you wouldn't have to use it at all, you just switched…
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I don't remember any CP/M system with the BIOS part in ROM (and BDOS loaded from disk). It would be possible, of course, but every subsequent version of CP/M for that machine would need to be able to work with the "frozen" BIOS, and I'm not sure CP/M was designed thinking of mixing BIOS/BDOS versions.Saying that, I think the Epson PX-4 and PX-8…
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Yes that early pdp-11s had core memory, its contents survived power cycling. We'd hand toggle in the bootstrap into high ROM and start it, it would load whatever we were running from paper tape - unless you did something stupid that trashed that high memory you'd get to reuse the bootstrap over and overHaving said that the bootstrap was something…
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So isn't the BIOS sort of an intermediary artifact?I think when CPM booted, there must have been some hardcoded disk firmware to get the boot sector into memory.The IBM PC bios was burned into the system.I think the boot process is multifaceted and can have as many stages.
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Kay nails it: the ENIAC 'BIOS' was literally a team of humans with patch cables. Makes you appreciate modern bootloaders.
All 3 developments of Alan Kay's old Quora answer on ENIAC's BIOS resurfaces on… →
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