Personal System/2 Model 25 Information and Software
System Type: 8525-001 or 8525-004
The IBM PS/2 Model 25 was released in 1987: its target market was geared towards schools and home users. This was especially signified by the use of ISA instead of MicroChannel: allowing existing home users to use their ISA cards without having to purchase new MicroChannel ones.
The all-in-one form factor was inspired from the competing Macintosh systems which came out in 1984.
Downloads
Pending
Key Features
- The Model 25 (along with the Model 30s) were the only computers to use the MCGA standard: which came out prior to IBM's VGA standard. Due to MCGA's limitations later VGA games may not run properly: it is possible to install a VGA ISA card and connect the internal CRT's cable to it with some minor modifications.
- Type 001 came with a monochrome CRT, Type 004 came with a colour CRT. The colour models had additional red/green/blue dots on the IBM badge to signify this as well.
- The HDDs used in these systems are proprietary ESDI drives with card edge connectors. They are not interchangeable with the similar card edge ESDIs used in the model 30(!) As such getting data off them is near impossible unless you have a PS/2 model 25. It would be a 'secure' way to store data, but as old hard disks can fail, definitely not recommended.
- The SIMMs used are proprietary to these systems; they can only be upgraded to a maximum of 1 MB of RAM; some of which is already used by the OS. The CPU can be upgraded with a NEC V30 for a *significant* performance boost and ability to run some 286 instruction sets.
If you have Model 25, I would advise upgrading it with a NEC V30 & Intel 8086-2 Math Co-Processor. Try to find a Model 25 already configured with a HDD and 1MB of RAM-- as finding the proprietary HDDs or HDD bays is very difficult.
Since there are only two ISA bays to work with, you will have to decide between the following:
Sound Card, Hard Disk Drive controller (if the proprietary HDD needs to be replaced), VGA card (if you need to override the MCGA for better VGA support).
Note: use a null modem with a serial or parallel port so you don't use one of the ISA slots up.