Author Archives: hottobar

CMOS battery replacement

Dallas DS1287

I received a couple of requests recently about the Model 2011’s RTC battery and how to replace it.

So I quickly arranged a mini how-to to explain the process.

How to replace the CMOS battery

Hope this helps.


PS/1 2123 ROM BIOS and starter diskette

PS/1 2123 Starter DisketteA couple of great additions for the Downloads section: the ROM BIOS and the starter diskette for the IBM PS/1 386SX Model 2123. – ROM BIOS, P/N 87F4794, dated 1992 – Bootable Starter Diskette with diagnostics software.

Note: the file 2123STRT.DSK inside the starter diskette archive is a stardard floppy image so you can use it with your preferred image transfer program.

Thanks Leo for the donation!

PS/1 2155-78C US preloaded software

Another donation: the preloaded software of the PS/1 2155-78C, US version.
The PS/1 2155-78C was a multimedia machine released in the US market during the spring of 1994 and equipped with:

  • Intel 486SX2/50
  • Cirrus Logic CL-5428 1MB VLB
  • 253MB HDD
  • 4MB RAM
  • Matsushita 2x CD-ROM drive
  • Creative Sound Blaster 16
  • Modem 2400 bps – HDD software as a recovery set (floppy images) – HDD software as simple files

Software included:

  • MS-DOS 6.21
  • MS Windows 3.1
  • MS Works for Windows 3.0
  • PS/1 tools, welcome
  • Prodigy
  • America Online
  • Photo Gallery
  • Co/Session
  • Sound Blaster 16 audio drivers and software
  • Cirrus Logic GD542x video drivers

Thanks Austin!

The mistery of the PS/1 2121’s (S)VGA

Working on the 2121 support in IBMulator, I started looking for any kind of information about the video interface.

According to IBM Corp., the PS/1 2121 has got a standard VGA with 256KB of memory, very much like the 2011’s one.

Actually, the chip used is the IBM 84F7985 / TI CF62011BPC. Unfortunately there’s no datasheet and information is very scarce (if you have any technical info please let me know!)

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