IBM PC Hard Drive (Fixed Disk) Images

Pre-built fixed disk images with the following sizes are available:

IBM PC XT Drive Types

The IBM PC XT BIOS supported 4 predefined drive types:

  • Type 0: 306 cylinders, 2 heads, 17 sectors/track (5,326,848 bytes)
  • Type 1: 375 cylinders, 8 heads, 17 sectors/track (26,112,000 bytes)
  • Type 2: 306 cylinders, 6 heads, 17 sectors/track (15,980,544 bytes)
  • Type 3: 306 cylinders, 4 heads, 17 sectors/track (10,653,696 bytes or ~10Mb)

Generally, our PC XT machines use 10Mb drives, configured as XT drive type 3. Such drives can also be used in our PC AT machines, but they must be configured as AT drive type 1 instead (see below).

IBM PC AT Drive Types

The IBM PC AT introduced a new drive controller and defined many new drive types. You can find a listing of them in the PCjs HDC component (see aDriveTypes).

Generally, our PC AT machines use four common sizes, which correspond to the following AT drive types:

  • Type 1: 306 cylinders, 4 heads, 17 sectors/track (10,653,696 bytes or ~10Mb)
  • Type 2: 615 cylinders, 4 heads, 17 sectors/track (21,411,840 bytes or ~20Mb)
  • Type 4: 940 cylinders, 8 heads, 17 sectors/track (65,454,080 bytes or ~62Mb)
  • Type 5: 940 cylinders, 6 heads, 17 sectors/track (49,090,560 bytes or ~47Mb)

Note that we don’t currently include any true Type 4 62Mb drive images. For drives that large, we generally use a COMPAQ DeskPro 386 machine, and COMPAQ Drive Type 4 specifies 1023 cylinders, not 940, which yields a drive capacity of 68Mb.