Image Map Image Map
Results 1 to 10 of 10

Thread: Burroughs "mini disk 3" 8" floppy disks

  1. #1
    Join Date
    Dec 2008
    Location
    United Kingdom
    Posts
    14

    Default Burroughs "mini disk 3" 8" floppy disks

    Hello

    I am looking for some information please on an unusual floppy disk format, photos attached.

    The disk is 8" but has no index hole or sector holes. Dates written on the disks range from 1983 - 1989.

    Does anyone know:-

    • The model of Burroughs system these disks were most probably used with?
    • The model of disk drive unit used with these disks?
    • Anything about the disk format (and ideally any documentation available that describes the layout, sector / track layout, data encoding etc.)
    • If anyone has a compatible disk drive available somewhere that can physically accept these disks (I appreciate that the disk drive alone is not sufficient to read data!)?


    Thank you in advance for your help.

    Cheers
    Robin
    Attached Images Attached Images

  2. #2
    Join Date
    May 2009
    Location
    Connecticut
    Posts
    3,398
    Blog Entries
    1

    Default

    Burroughs only made 3 basic types of floppy drives so it can't be that hard to determine. However, most used 9489 with a suffix. 9489-17/18 was equivalent to IBM's original drive; 9489-11/12 were 1 MB drives and I think the disks were labeled as Mini Disk 2; that leaves the 3 MB 9489-2x line.

    1) The only web reference to Mini Disc 3 is in conjunction with an Australian sale of B9000.
    2) Probably would be 9489-2x (21, 23, 27 are sub-models I have seen references to) or perhaps the OEM variation called the MD-122
    3) Double sided disk with 142 tracks at 10,620 bytes per track. MD 122 cuts the tracks to 139 but increases 11,264 bytes per track. Figures taken from old Disk Trends.

    Maybe that could point you in the right direction? There are a few museums that claim to have to Burroughs floppy information but it is not online. How did you get those disks?

    http://www.picklesnet.com/burroughs/gallery/bpgb90.htm has pictures of the Mini Disk 2 which looks completely different so your disk can't go into that drive.
    Last edited by krebizfan; September 13th, 2017 at 07:30 AM.

  3. #3
    Join Date
    Jan 2007
    Location
    Pacific Northwest, USA
    Posts
    25,019
    Blog Entries
    20

    Default

    The disk has more than a passing similarity to the Memorex 650 system.

    http://bitsavers.informatik.uni-stut...0floppyOEM.pdf

    Is the hole near the "Burroughs" logo an index hole?

    Edit Forgot to add that this should be a scant surprise, since Burroughs acquired Memorex in 1981--and Memorex operations supplied Burroughs with its storage products.
    Last edited by Chuck(G); September 13th, 2017 at 11:14 AM.

  4. #4
    Join Date
    Sep 2006
    Location
    Silicon Valley
    Posts
    1,212

    Default

    The MD 122 dual 3 Mbyte flexible disk drive

    http://ieeexplore.ieee.org/document/1061253/

    Abstract:
    The dual 3Mbyte flexible disk drive provides 6 Mbyte of formatted data storage in a compact package designed for in-built use. The two disks may be inserted or removed independently and share a common double ended spindle. A common actuator is used to position the four recording heads. High areal recording density is achieved using advanced technology recording heads and media in association with a microprocesor controlled environmentally compensated servo positioner. The drive incorporates an intelligent controller which provides sophisticated data handling functions and controls the drive in such a manner that the interface to the host is free of drive dependant parameters.

    IEEE Transactions on Magnetics ( Volume: 17, Issue: 4, Jul 1981 )

    --

    also patent 4492992 on the servo positioner

    I've had a couple of boxes of these for a long time now.

    There are press photos for the B90 series with the 6mb drive in the front.
    Earliest I've found are Electronics News Oct, 1979 calling them Super Mini-Disk II (SMP II)

    --

    just found the product spec and brochure in the jim porter archive

    will try to get it posted by noon so the mirrors pick it up

    --

    done
    Last edited by Al Kossow; September 13th, 2017 at 11:56 AM.

  5. #5
    Join Date
    Sep 2006
    Location
    Silicon Valley
    Posts
    1,212

    Default

    One last thing, I was able to get the IEEE article on them, they are 155tpi, servo tracking, and the heads are designed to fly 8 microinches above the surface.

    Ain't no way you're going to read these on anything other than what they were designed for.

  6. #6
    Join Date
    Jan 2007
    Location
    Pacific Northwest, USA
    Posts
    25,019
    Blog Entries
    20

    Default

    I find a mention in Confuserworld from 1976 on the AE400 System.

    Al, I assume that the B91 brochure you're talking about is this one.

  7. #7
    Join Date
    Sep 2006
    Location
    Silicon Valley
    Posts
    1,212

    Default

    Quote Originally Posted by Chuck(G) View Post
    I find a mention in Confuserworld from 1976 on the AE400 System.

    Al, I assume that the B91 brochure you're talking about is this one.
    The 1mb from 1976 is the double sided hard sectored disk II
    The picture of the B91 with the disk III is up now on bitsavers under burroughs/B90/B90_19791008.jpg
    All of the floppy document scans are under burroughs/floppy

  8. #8
    Join Date
    Dec 2008
    Location
    United Kingdom
    Posts
    14

    Default

    All, thank you for this information. Sounds like the design was more like a hard drive than floppy - what with built-in servo system and heads flying above the media surface.

    For my purposes the IEEE article in particular could be very helpful. Al Kossow, is the IEEE article you are referring to the same one that Chuck mentions?

    Do you have any ideas about whether or not one of these drives is still in existence? Do you have any good contacts I could reach out to with a request?

    Thanks
    Robin

  9. #9

    Default

    Just happened to see this Ebay auction. Is it the drive for this disk?

    But it has a stepper. Not servo so it is probably something else.
    Last edited by MattisLind; September 15th, 2017 at 07:18 AM.

  10. #10
    Join Date
    Sep 2006
    Location
    Silicon Valley
    Posts
    1,212

    Default

    Quote Originally Posted by MattisLind View Post
    Just happened to see this Ebay auction. Is it the drive for this disk?
    No, that is a 1mb hard-sectored "Disk II"

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
  •