Talk:List of IBM Personal Computer models
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Should be renamed List of IBM computer models
[edit]The list is supposed to include ALL the computers from IBM, so "Personal Computer models" is wrong IMO. Tactica (talk) 10:15, 26 May 2024 (UTC)
- No, this list should only encompass models in the original IBM PC line. IBM has produced a wide variety of computers besides PCs: mainframes, minicomputers, workstations, servers, point-of-sale machines, etc. A monolithic list article for all those lines would be incredibly large and unwieldy. Those are best reserved for separate list articles. DigitalIceAge (talk) 16:09, 26 May 2024 (UTC)
Some notes on early IBM PC models
[edit]What I'm about to say is going to need to be backed by citations if integrated into the article.
Michal Necasek (from OS/2 Museum) did some digging and found some likely specifications: IBM PC 5150 Model Numbers
It might be tricky to prove some of what's in Michal's blog post conclusively, but if something doesn't match what is written there then there's probably a citation which backs up Michal's claims.
There's also a forum thread from 2018 linked in the blog article with one person trying to make sense of it all: IBM 5150 Board Switches - PCem
...
The thing which got me to fix some of the specs in the first place is this little tidbit: If an IBM PC has less than 32KB of RAM, it cannot boot off of a floppy disk or a hard disk - it can only run IBM Cassette BASIC, which can only access the cassette tape drive for reading and writing (unless one wants to dig into the system internals). This is because the bootloader places the boot sector (usualy 1/2 KB, but potentially 1KB on some weird systems which may or may not exist) at the 31KB mark in RAM.
Which means that an IBM PC shipped with a floppy drive almost certainly comes with more than 16KB of RAM. This is testable in 86Box! It turns out that if a floppy drive is attached to a PC with 16KB of RAM... the system actually hangs on boot if there's a bootable floppy in the drive.
Ralf Brown's Interrupt List covers the bootloader protocol in the INT 19h (section "B-19" in INTERRUP.D), but doesn't touch on the matter of 16KB PCs at all.
So it's probably not particularly strong evidence of what I'm claiming on this talk page. But feel free to use it as a sanity check. CognitoLeaf (talk) 22:48, 31 March 2025 (UTC)