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IBM 5170  -  Determining the Hard Drive Type Number


Presumably you are here because you are trying to determine the 'IBM type number' of a hard drive (fixed drive) in your IBM 5170.
The type number is used in the SETUP of the 5170.

Following are three methods of determing the IBM type number.


IMPORTANT:   The following assumes that your IBM 5170 motherboard is fitted with IBM 5170 BIOS ROM's (i.e. not swapped out for non-IBM ones).
Although authors of other BIOS' often mimicked IBM (to maintain IBM compatibility), some authors did not.
Example: A Seagate ST-4038 drive is a type 20 on an IBM 5170, but a different type number on certain ALR computers.



Method 1 - Sticker

If your 5170 has its original drive (or authentic replacement), then the IBM type number can be easily determined.
On IBM's direction, makers of hard drives for the IBM 5170 placed the number on the front of the drive.
In the photo below, the large "2" means that the drive is an IBM type 2.

5170_type_2_example.jpg



Method 2 - Some Known Drives

Obtain the maker and model number of the hard drive, and see if it matches one in the following list.

Make and Model IBM Type  Comment
CMI model 6426 2  MFM.
IBM 0665-30 2  MFM.  '30' is the unformatted capacity.  About 20 MB formatted.
IBM 0665-38 20  MFM.  '38' is the unformatted capacity.  About 30 MB formatted.
IBM 0665-53 21  MFM.  '53' is the unformatted capacity.  About 43 MB formatted.
Seagate ST-4026 2  MFM.
Seagate ST-4038 20  MFM.



Method 3 - Unlucky Last

1.  Obtain the maker and model number of the hard drive, e.g. Seagate ST-225.

2.  From the Internet, use the information determined at step 1 to determine:
     • Count of cylinders
     • Count of heads
     • Sectors Per Track (SPT)
     • Write Pecompensation Cylinder (WPC)

     If the Internet source doesn't show the rated SPT for the drive, then assume an SPT of 17.

3.  Using the information determined at step 2, find a match in the following table.
     If you can't find a match using all 4 figures, but there is a match if WPC is ignored, then use that match.
     If you still can't find a match, see here.

  Cylinder
Count		 Head
Count		 SPT WPC  Comment
Type 1 306 4 17 128  
Type 2 615 4 17 300  
Type 3 615 6 17 300  
Type 4 940 8 17 512  
Type 5 940 6 17 512  
Type 6 615 4 17 none  Some Internet sources may show no WPC as "N/A" or "-1" or "65535"
Type 7 462 8 17 256  
Type 8 733 5 17 none  Some Internet sources may show no WPC as "N/A" or "-1" or "65535"
Type 9 900 15 17 none  Some Internet sources may show no WPC as "N/A" or "-1" or "65535"
Type 10 820 3 17 none  Some Internet sources may show no WPC as "N/A" or "-1" or "65535"
Type 11 855 5 17 none  Some Internet sources may show no WPC as "N/A" or "-1" or "65535"
Type 12 855 7 17 none  Some Internet sources may show no WPC as "N/A" or "-1" or "65535"
Type 13 306 8 17 128  
Type 14 733 7 17 none  Some Internet sources may show no WPC as "N/A" or "-1" or "65535"
Type 15          Do not use. More information.
Type 16 612 4 17 0 (all)  Not available in the 01/10/84 dated motherboard BIOS)
Type 17 977 5 17 300  Not available in the 01/10/84 dated motherboard BIOS
Type 18 977 7 17 none  Not available in the 01/10/84 dated motherboard BIOS
Type 19 1024 7 17 512  Not available in the 01/10/84 dated motherboard BIOS
Type 20 733 5 17 300  Not available in the 01/10/84 dated motherboard BIOS
Type 21 733 7 17 300  Not available in the 01/10/84 dated motherboard BIOS
Type 22 733 5 17 300  Not available in the 01/10/84 dated motherboard BIOS
Type 23 306 4 17 0 (all)  Not available in the 01/10/84 nor 06/10/85 dated motherboard BIOS'