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  1. M

    ROM inline with a floppy?

    Back in the eighties there were products that offered a real time clock that went between your floppy drive and the controller. Would it be possible to do this with a ROM chip as well? The idea would be to give an older PC 1.44MB support without using a card slot.
  2. M

    Minus Zero Degrees IBM XT memory mod.

    This article talks about adding 640K to an older XT motherboard. It says you add the 32KB chips to bank 0 and 1. My questions is whether or not I will get 1MB if I also put 32KB chips in banks 2 and 3. (along with the appropriate UMB driver)
  3. M

    2/66Mhz vs 33Mhz

    I was playing with my big discrete logic board 486 again, and discovered that an unmarked jumper selects how the oscillator crystal is used. The normally fixed position that the board was sold with runs a 66Mhz oscillator which is divided somewhere and appears as 33Mhz at pin C3 on the CPU...
  4. M

    Why is this board so fast?

    Well, fast for a given value of fast, anyway. ;) Nonetheless, with an Intel DX2 66 (write through) and a Cirrus Logic GD5422 (STB Horizon), I get 6.8 FPS in the Quake Time Demo. I cannot get any of my other 486 boards to match that, using the same CPU and video card. The all ISA Symphony board...
  5. M

    Need a new ROM Programmer.

    Well, it seems my trusty GQ-4X4 has hit the floor too many times and now no longer works. I originally bought it after a disastrous attempt to use a TL866, which bricked itself on the first run of the software. I am planning on getting another GQ-4X4, but I wanted to stop in here and see if...
  6. M

    amount of cache vs amount of memory.

    When it comes to cacheing ram, I understand one needs: 64KB for 8MB 128KB for 16MB 256KB for 32MB 512K for 64MB ..and so on. Is there any advantge to be had by having more than required amount for a given amount of ram? Like having 256K cache in a system having only 8 MB of ram?
  7. M

    Trouble shooting a 286.

    No name discrete logic board, believed to have been made by Everex. Bought it, would only occasionally turn on and 'post'. This was a message complaining saying, depedning on which keyboard controller I put in there, would say '8042 error' or 'Gate A20 error'. Replaced about 40 10uf caps...
  8. M

    Cheetah 16bit ISA 640/2.5MB RAM card manual + software

    Sorry for the 20MB PDF file. I may try shrinking it some other time. http://www.filedropper.com/cheetah Spread it around the web.
  9. M

    35v caps on 286 board?

    I've got a 286 board I want to recap, but it has 35 volt tantalum caps all over it. Is there a reason they would have used these over 16 volt caps, other than maybe they got a good deal on 35 volt ones?
  10. M

    Are there any 286's that deturbo to 4.77Mhz?

    Preferably an 8/10/12Mhz machine. I actually have a 286 powered XT board (Hedaka 919) that does this, but I was wonder if there are any proper fully 16 bit boards that de-turboed to 4.77Mhz?
  11. M

    Can the IBM 5162 be upgraded, speedwise?

    Provided the correct Crystal, CPU, and RAM is in place, can the XT286 go faster than 6Mhz, or does it also have those ROM routines that prevent this like some of the ATs do?
  12. M

    Are there any apps that let you use your cell phone as a modem?

    In conjunction with a usb to serial adapter?
  13. M

    Is the UMC UM82C491F chipset a known terrible chipset?

    I have 2 motherboards from different manufacturers. They both have 256K cache. I have tried the same AMI BIOS ( and the same Mr. BIOS (recently posted on Vogons). Both were tested with two different 16MB ram sticks and two different DX2s. I have combed over the BIOS settings and jumper settings...
  14. M

    Tandy Smartwatch+

    Has anyone bought one of these Tandy Smartwatch+ units from here? Do they only work with Tandy machines? I know my IBM XT had a very similar device inserted between between the board and 32K system ROM chip, but that didn't have a provision for a battery.
  15. M

    Why are terminals still so expensive?

    I noticed when browsing Ebay the other days that terminals still go for quite a bit of money. Is there a particular reason for this?
  16. M

    For anyone that has the IBM PGC...

    Have you ever tried sticking an NEC V20 in it? Would it improve performance?
  17. M

    P66, POD83, and AM5x86 133 comparison.

    Made this awhile back and posted it to VOGONS, though it garnered no responses. Just found it again. Nothing hugely detailed, just some scored from Phil's Benchmarking pack. Options 2, 4, 6, B and C were used.
  18. M

    Another discussion of CGA/EGA on (relatively) modern monitors.

    I know this horse has been beat to death, but I stumbled across this video by 'Artifact Electronics' the other day where in the process of examining the old PC clone in question, the individual goes about connecting a CGA (though I actually believed that to be an EGA card when he shows it at...
  19. M

    Is there a BBS setup up for testing purposes?

    I got my first modem in 15 years, a Tandy AC-4 acoustic coupler (and a retro handset connected to cell phone). By the time I came along in the world of computing, 56k click-and-connect was the way things were done, so this whole modem/serial port/terminal thing is new to me, and I'd rather not...
  20. M

    For you monochrome lovers out there, which phosper do you prefer?

    Amber? Green? White? I have always preferred amber myself, though I don't have one in my possession. Might try to find a 9" amber tube for my luggable.
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