Talk:IBM Personal Computer/AT
From Wikipedia, the free encyclopedia
Contents |
[edit] Advanced Technology?
Because the AT used various technologies that were rare at the time in personal computers, the name AT originally stood for Advanced Technology. Is this accurate? True, the AT came with a hard drive which was sort-of advanced. And Mueller's book says "AT" stands for "Advanced Technologies". I think the bit-mapped display of the contemporary Macintosh was a bit more advanced than the AT video display, but Macintoshes were rare at that time, too. The AT came with a real-time clock and CMOS to set up the system, unlike the DIP switches that the origianl PC had. I suppose that's an advance. --Wtshymanski 00:38, 8 Jun 2005 (UTC)
It was advanced from IBM's point of view, regardless of what Apple was doing then. The XT (eXtended Technology), which predated the AT, had a hard drive.
[edit] Keyboard
The article should note that the AT keyboard is not compatable with the IBM PC or PC/XT or clones thereof, and that many keyboards were produced with an XT/AT or PC/AT switch to work with either until the PC and PC/XT systems began to be phased out of use in the early 1990's. (I saw many lots of PC and PC/XT systems sold at auctions for a few dollars a pallet in 1990~1992.)
- It should be noted that the AT keyboard is incompatable with the PC and PC/XT for these two reasons. 1. Different scan codes. 2. The A20 gate control circuitry is in the keyboard. The A20 gate is used for switching to Protected Mode. An IBM AT (or any clone without a 'fast A20' BIOS setting or setting to boot without a keyboard or to not test the keyboard during POST) will not function at all without a keyboard connected. Later clones moved the A20 control onto the motherboard and had a 'Fast A20' setting in the CMOS setup to use it, then could be booted without a keyboard.
[edit] Power Supply
I don't recall ever seeing a pushbutton swtich at the end of a power cable. I thought the PC and XT (and possibly AT) had huge orange toggle switches, while modern ATX supplies have rocker swtiches.
- Most later AT cases, especially tower styles, had the power switch (toggle, rocker, or locking pushbutton) mounted on the case front and used four wires carrying line current between the switch and the power supply. Some proprietary OEM manufacturers, like Packard Bell, used a long plastic or metal rod that pushed a switch inside the power supply case. At least one company used a toggle lever with a metal wire rod that moved an internal toggle switch mounted on the power supply.
[edit] DMA channels
16 DMA chnnels? I don't understand. I have always thought DMA channels were from 0 to 7. —The preceding unsigned comment was added by 82.155.155.251 (talk • contribs) 19:40, June 30, 2006 (UTC)
- It seems you are correct. The incorrect number in the article was copied from a web site with bad information. Thanks for the heads up. --Blainster 00:41, 6 July 2006 (UTC)
[edit] Who deleted this?
Why is this article deleted? This is certainly notable enough for Wikipedia. —The preceding unsigned comment was added by Nick Warren (talk • contribs) 06:27, September 19, 2006 (UTC)
- The article has not been touched in nearly three weeks. Did someone steal your account to make this edit?--Blainster 22:06, 19 September 2006 (UTC)
No, it looks deleted to me. I'm serious. I could take a screenshot and show you if you don't believe me. I'll go look at it through a proxy and see if it looks deleted... Nick Warren 04:58, 20 September 2006 (UTC)
Well, my initial theory seems incorect. It also looks deleted to the proxy, so it's not just me. Does it really nto look deleted to you? Weird. Nick Warren 05:01, 20 September 2006 (UTC)
- The page looks fine to me. I recently saw an image page that was redlinked, but had the image there plain to see. I assume that was a system bug. Is that what you see here? --Blainster 21:46, 20 September 2006 (UTC)
Something was messed up. I re-saved the page and it comes up now. Mirror Vax 22:00, 20 September 2006 (UTC)
- Maybe the database servers are really slow, but I'm still seeing September 1, 2006 as the last edit. --Blainster 23:18, 20 September 2006 (UTC)
- That's right. Re-saves never appear in the history (try it). Mirror Vax 00:04, 21 September 2006 (UTC)
OK, it looks fine now. What happened?Nick Warren 11:53, 22 September 2006 (UTC)
