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I was looking into the available docs and firmware for this system (http://bitsavers.org/pdf/ibm/system23/), to try and figure out how this thing handles text display. Naturally I don’t have one of these – I’m just a certified nutter for bitmap font stuff, but the System/23 is particularly...

Maybe I'm having an extreme case of delayed ignition, but it seems that a lot of content from the old pre-migration forums is completely MIA. To be clear, I'm not referring to the separate issue of broken links in older threads (where the content may still exist, but cannot be accessed with the...

https://twostopbits.com/ Not mine, and I'm not affiliated with it... but I like the idea.

(Preamble: to most of you, this will seem like OCD nitpicking of the worst kind, but it ain't so. Fact is, I'm working on a graphical project which targets the IBM Color Display, and accurate colors become important for the artwork, especially when you factor in things like dithering.) Some of...

I have a couple of computer dust covers, but they were obviously made for later PCs... with much larger monitors and much smaller desktop footprints. Looking for something made for an IBM XT with Color Display. Or at least close enough so it wouldn't look like an embarrassing mismatch between...

Happened to me and to others as well. Mentioned in the long 'new forums' thread, but I'm reporting this separately here in case that one gets lost in the shuffle. For me, it happened after I submitted a post, and then quickly edited it only twice (or maybe 3 times?): Seems arbitrary...

A couple of questions I have about how text output works on the Model 2000. I don't own one so I can't answer them myself, but call it historical research. In text mode, is 10x16-pixel character display a real thing or not? The 2000's graphics resolution is 640x400, and a matching 80x25 text...

The full model designation on the back is "SC-452A2", but the interwebs is drawing a total blank on that, so "SC-452" may have to do. My options for obtaining this type of document seem to be Buy a purported PDF from one of a veritable legion of websites, all of which look about as legit as...

I've been offered a certain monitor (IBM 5153) by a friend in Germany, and we're trying to work out how to get it from him to me. I haven't had much luck with these things so far (read: two shipped CRTs gone to the Great Parts Bucket in the Sky this year), but maybe third time's the charm...

Not sure whether this should be posted here, or in the Off-Topic section, since this project of mine isn't actually usable *on* a vintage machine. Still, it's my own way of preserving a small but distinctive part of the oldschool PC experience, even in more "modern" environments. Come check it...

https://devblogs.microsoft.com/commandline/microsoft-open-sources-gw-basic/ https://github.com/microsoft/GW-BASIC Now, I'm hoping that they'd go one further and release the sources for BASCOM as well. Those compiled-BASIC executables take the cake in being annoying to disassemble/debug...

If you have one of these (in working order): - Leading Edge Model D (with a color and/or mono monitor) - Olivetti M15 / M15-Plus - Olivetti M211v / M316 - Sanyo MBC-775 - Sanyo MBC-16 - Amstrad ALT-286 ...then I'd like to kindly request your help with a project that I'm working on. Your...

I'm looking for a CGA monitor for my 5160, in good/working condition. Trying here because I've about given up trying to source one from the usual channels. Since the machine is IBM, I'd prefer the 5153, but I could also go for a CGA monitor with the same design, to preserve the look...

Consider the following scenario: let "background" and "foreground" be two layers of visual data, composed of 16-bit values. I'd like to merge them as follows - for each offset, if foreground contains zero, it is considered transparent (=use the background value). Otherwise, use the value in...

The system is a 5160 (third revision BIOS, XTIDE Universal BIOS v2.0.0b3), with a half-height 5.25" floppy drive and the IBM Diskette Drive Adapter (w/Intel P8272A), running MS-DOS 6.22. Been reading quite a lot of data off some floppies. Every once in a while, a perfectly good disk would give...

I've finally started dumping a rather sizable pile of floppies, which date back from my family's first no-name XT clone (~'87 or so). The first batch turned up a copy of the TSR attached here, which is related to the video adapter. One thing I don't really know is what video adapter we...

I'm looking for a way to query DOS and enumerate all available drives in the system. My target is MS/PC-DOS 3.0 and above. For floppy drives, the sample code at http://www.fysnet.net/getdrvs.htm uses an acceptable method (already discussed here in the past). For non-floppy drives however...

Here is what I get from available documentation. Before making changes to the VGA clocking mode (i.e. doubling/halving the character clock for 40/80 column operation, or toggling 8/9 dots per character), the sequencer must be reset first - using the Sequencer Reset Register (port 3C4h, index...

Here's a card that just came in the mail. 1804464 was one of those "unknown type" CGA P/Ns (see this old thread) - i.e., it wasn't known whether it had an older-style or newer-style composite video output. Having tested it now on my TV, I can confirm that it definitely shows an older-style...

For my own purposes I need to test some self-booting IBM PC sofware in a slightly altered environment. More specifically, the idea is to boot first into my own code, which does the following: - Copy a small BIOS data table to somewhere in RAM and modify it - Target the relevant pointer (in the...