Talk:IBM Monochrome Display Adapter

message: What pin numbers? Shown is the end of the connector without any numbering.— Preceding unsigned comment added by 216.188.252.240 (talk • contribs) 
:It would seem that when the above comment was added, this revision was current, but the issue complained of back then has long since been resolved. —ReadOnlyAccount (talk) 22:25, 1 December 2023 (UTC)
thread_title:  Pin numbers 

message: :Image:Executive-Suite-DOS-1982.png is being used on this article. I notice the image page specifies that the image is being used under fair use but there is no explanation or rationale as to why its use in this Wikipedia article constitutes fair use. In addition to the boilerplate fair use template, you must also write out on the image description page a specific explanation or rationale for why using this image in each article is consistent with fair use.
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BetacommandBot 03:52, 1 October 2007 (UTC)
thread_title: Fair use rationale for Image:Executive-Suite-DOS-1982.png

message: are you sure the pixel resolution of MDA is 720 x 350? When i take a screenshot of ibm pc emulators without scaling i get a 720 x 400 Pixel image out of it... 2001:9E8:6345:9700:35EF:ADC7:82E5:1948 (talk) 16:03, 1 November 2023 (UTC)
replies: text: According to "Upgrading and Repairing PCs, 2nd Edition" by Scott Mueller(Que Books, 1992), table 10.1 on page 672, the monochrome display adapter has an effective resolution of 720 * 350, since it displays 80 columns of characters in 25 rows with a 9 by 14 character cell. A screen shot of an emulator is original research and not an acceptable reference for Wikipedia. --Wtshymanski (talk) 03:05, 5 November 2023 (UTC)
replies: text: 720x400px is the resolution of VGA card colour and monochrome 80x25-character text modes (character matrix 9x16px). A VGA card would use that in lieu of an actual MDA card's 80x25-character text mode output, which indeed was 720x350px (character matrix 9x14px). This means that when you used BIOS video mode 07h, results were not necessarily pixel-identical on all PCs. Close, but no CD. What you got depended on whether your PC sported an MDA/Hercules/EGA or VGA card. (Herc and EGA should've been pretty much pixel-identical with MDA in that mode, though perhaps some character ROMs had minor differences.) –ReadOnlyAccount (talk) 21:05, 1 December 2023 (UTC)
thread_title:  Resolution 

message: I feel this recent addition to the article raises more questions than it answers. Does the cited assertion that the presence of an MDA card could halve the bus speed mean all MDA cards and clones did this, or only some? Did original IBM MDA cards do this? Did only some or all clones? Is 4MHz a rounded figure, or was even the original 5150/5160 PC/XT machines' bus speed also reduced, down from 4.77MHz? (I presume on those early machines running slower than 8MHz, bus speed was identical with CPU speed?) Was the speed limitation something that only negatively affected VGA card performance in dual-monitor systems given how VGA demanded more of the bus, or was there a speed impact that was noticeable absent a VGA card as well? What about CGA+MDA dual-monitor setups? Were there ever any 16-bit ISA MDA cards or clones available? I'm not against the inclusion of the cited concern in the article, but it's not very clear, and the section could benefit from expert attention. —ReadOnlyAccount (talk) 20:22, 1 December 2023 (UTC)
replies: text: The I/O Channel Ready line is a handshake that allows older cards to pause the bus clock while they retrieve data. This mechanism allows the bus speed to be decoupled from the processor speed and for different cards to access the bus at different speeds. The performance impact would only be while the MDA is actively using the bus but this could gum things up enough to affect performance of a VGA card connected to the same bus. ~Kvng (talk) 15:34, 15 May 2024 (UTC)
thread_title:  Disadvantage