Image Map Image Map
Page 1 of 3 123 LastLast
Results 1 to 10 of 23

Thread: Seagate MFM drive model numbers and differences ?

  1. #1
    Join Date
    Jan 2019
    Location
    New Hampshire
    Posts
    241

    Default Seagate MFM drive model numbers and differences ?

    Hey everyone, I'm curious to learn more about Seagate MFM drive part number variations ... the usual suspects, ST225, etc.

    I've seen a random few drives with "MLC" following the model number, ex: "ST-251 MLC-1" What is the meaning of MLC-1?

    I've also seen some part numbers like "ST-251 -1". Same curiosity... what does -1 specify?

    Of course the "R" versions are RLL rated drives. How about the "AT" drives? Is the logic board any different or are they the same as the regular models?

    These are fascinating drives, and I'm finding that many of them still work quite well.

    Thanks to anyone who might have insights on the model number variations!

  2. #2

    Default

    RLL drives have a little more band width than non-RLL otherwise the are the same. The - numbers are usually newer revisions.
    AT drives have the controller built in and would be connected directly to the data buss.
    The main differences to the drives are things like stepping speed(some have auto-stepping), number of head, number of sectors and sometimes rotational speeds.
    Dwight

  3. #3
    Join Date
    Jan 2013
    Location
    Marietta, GA
    Posts
    3,491

    Default

    My memory is a bit vauge but as I recall:
    R at the end indicates and RLL drive, N at the end indicates SCSI, A at the end indicates IDE. I think sometimes the SCSI and IDE would be the same hardware assembly with different logic boards.

    I think -1 or MLC-1 at the end indicates a Seagate "refurbished" unit. I seem to recall these would usually have longer track defect lists.

  4. #4
    Join Date
    Jun 2015
    Location
    Sioux Falls SD
    Posts
    388

    Default

    Then there are A/X drives which can be connected to either AT (16-bit) or XT (8-bit) IDE ports. One drive that I know of is only 8-bit IDE, which is the ST325X.

  5. #5

    Default

    Quote Originally Posted by SomeGuy View Post
    I think -1 or MLC-1 at the end indicates a Seagate "refurbished" unit. I seem to recall these would usually have longer track defect lists.
    No, MLC stands for Manufacturing Line Code - or something like that. The ST-251 for example has the same stepper as the ST-225, but the ST-251-1 (or ST-251 MLC-1) is fitted with a low-impedance stepper that drops average seek times from around 65 to around 20.

  6. #6
    Join Date
    Jan 2019
    Location
    New Hampshire
    Posts
    241

    Default

    Quote Originally Posted by maxtherabbit View Post
    No, MLC stands for Manufacturing Line Code - or something like that. The ST-251 for example has the same stepper as the ST-225, but the ST-251-1 (or ST-251 MLC-1) is fitted with a low-impedance stepper that drops average seek times from around 65 to around 20.
    Yes, that's exactly what I was looking for. Really, I was wondering if the circuit board from an MLC-1 would be the same ... I found a possible donor board for an st251, but it is on an MLC-1 model. Do you know if the circuit board is different to drive the different stepper motor?

    I have a few different models of these drives, I understand RLL/mfm drive metrics well, just needed some clarification of the differences like "mlc" and "-1". Thanks for the excellent answer maxtherabbit.

  7. #7
    Join Date
    Jan 2019
    Location
    New Hampshire
    Posts
    241

    Default

    Quote Originally Posted by lafos View Post
    Then there are A/X drives which can be connected to either AT (16-bit) or XT (8-bit) IDE ports. One drive that I know of is only 8-bit IDE, which is the ST325X.
    Yes, I believe you are correct for the early 3.5" IDE models. I have a working A/X drive in a 386.

  8. #8
    Join Date
    Jan 2013
    Location
    Marietta, GA
    Posts
    3,491

    Default

    Quote Originally Posted by maxtherabbit View Post
    No, MLC stands for Manufacturing Line Code - or something like that. The ST-251 for example has the same stepper as the ST-225, but the ST-251-1 (or ST-251 MLC-1) is fitted with a low-impedance stepper that drops average seek times from around 65 to around 20.
    Hmm, OK, so was there a code for "refurbished" unit?

  9. #9

    Default

    Quote Originally Posted by SomeGuy View Post
    Hmm, OK, so was there a code for "refurbished" unit?
    I'm not sure, I only learned about the 'MLC' like last week

  10. #10
    Join Date
    May 2006
    Location
    Melbourne, Australia
    Posts
    6,668

    Default

    Part of the story:


Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •