IBM 5150  -  Hard Drive Support


Early versions of the 5150

Initially, there was no IBM support for hard drives at all.   The barriers were:

• DOS 1.0 and 1.1 had no hard drive support.
• The BIOS on the 5150 motherboard has no support for hard drives.
• 'BIOS expansion ROM' functionality did not exist at this time.
• The IBM 5150's 63W power supply was inadequate to power both the 5150 and hard drives of the time.

However, some third-party solutions emerged.  They involved an externally powered hard drive, and custom boot floppy.
An example is detailed at here.
Another example is the 'HardFile System' by Tallgrass Technologies.

Later versions of the 5150

EARLY 1983

Early 1983, some significant events occurred.  The IBM 5160 (IBM XT) and DOS 2.0 were released, and they supported hard drives.  The BIOS on the 5160 motherboard introduced support for BIOS expansion ROMs, and so now it was possible for a hard drive controller card to have its supporting BIOS located within a ROM on the card.

About this time is when a new revision of motherboard BIOS appeared for the IBM 5150, the 10/27/82 revision, and it too had support for BIOS expansion ROMs.

So at this time, someone with a 10/27/82 BIOS equipped IBM 5150 could fit an XT-class hard disk controller, a hard drive, and run DOS 2 - all that would need to be worried about was whether or not the 5150's 63W power supply was going to be adequate for the task.  But at the time, it was not adequate (due to the power requirements of current hard drives).  It is the reason why IBM put a 130W power supply in the 5160.  The diagram at here shows that the +12V start-up power requirement of the Seagate ST-412 easily exceeds the +12V power rating (24W) of the 5150's 63W power supply.

At this time is when IBM offered a hard drive solution for the IBM 5150.  It was the attachment of an IBM 5161 expansion unit (one that contained a hard drive and controller) to the 5150.

POST 1983

Hard drives became physically smaller, and their power requirements smaller.  Therefore, the 5150's 63W power supply becomes less of an issue.  For example, it is reported that a Seagate ST-225 works okay with the 63W power supply.


Some modern options:

James Pearce's XT-CF-Lite card
Sergey's XT-CF-Lite card
XT-IDE card with a CF-to-IDE adapter   (XT-IDE info here)

Note that all require that the IBM 5150 motherboard has the 10/27/82 revision of BIOS.