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Re: Hi & a question

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  • alltare
    Welcome to the group. I haven t heard of any designs for using 3 drives. The Altair software and hardware was all designed around hard-sectored diskettes,
    Message 1 of 3 , Feb 7 10:56 AM
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      Welcome to the group.

      I haven't heard of any designs for using 3" drives. The Altair
      software and hardware was all designed around "hard-sectored"
      diskettes, and that may prove to be the biggest problem. I have
      never seen a hard-sectored 3" diskette- only soft-sectored.

      Of course, there were many other S-100 systems that did use soft
      sectoring, It might be a fairly simple task to do some timing
      changes on one of those old controllers for use with 3" disks. I
      don't know the rotational speed of 3" drives, but I think 8" and 5"
      ran at 360 and 300 RPM. Whatever the speeds, though, you would have
      to compensate for rotational speed differences by making timing
      changes to the circuits that generate the sector and byte timing. I
      could be full of beans here, but this approach doesn't immediately
      seem like it would be a major task. What do you other members think
      about this?

      Done this simply, you wouldn't be able to use the 3" to its full
      1.4MB capacity. You would still only use as many tracks as the
      original system, and as many bytes per track as the original system,
      and most likely only one side of each disk. There would be a lot of
      wasted potential, but at least you would be using "state-of-the-art"
      diskettes and drives (or maybe not so state-of-the-art. I just read
      that Dell will discontinue installing floppies on most future systems
      in favor of CDs). I recall that an 8" floppy back then held 320 to
      360 KB on about 80 tracks. I think 5" floppies held about half that
      much data per side on half as many tracks. It's been a long time,
      so don't take any of my numbers too literally, but I think I'm in the
      right ball park.

      What I would like to see is a CD burner that could be used in an
      Altair system, using Altair BASIC, that looked to the system like its
      own hard drive or floppy drive (now THERE'S a waste of space). All
      of that old software is rotting away on 25 year old diskettes and
      really needs to be archived on the more permanent CD medium. If you
      ever see anything like that, please tell us about it.

      I look forward to seeing your pictures.

      Steve
      ============================

      --- In altaircomputerclub@yahoogroups.com, "Larry Troth" <larry@u...>
      wrote:
      > Hello
      >
      > I have just joined the group and I am looking forward to gaining
      some new
      > knowledge regarding the old hardware that I have. After 20+ years
      in
      > storage, I will finally be able to get my s-100 systems (yes, I have
      > several) bake in operation. As I get them up I'll post pictures
      and info.
      >
      > My question is about some new hardware for these old systems.
      While I have
      > a good supply of 8" floppy drives and floppies, it is only a matter
      of time
      > till the last of them give up the ghost. Has anyone come up with a
      > kit/board/schematic/??? to allow the use of the new 1.44Mb 3-1/2"
      diskette
      > drives with these old systems? I would love to transfer my old
      data from
      > the 8" media to the 3-1/2" media. Does anyone know of any web
      pages that
      > discuss this? Are there any resources out there? (I found a site
      that has
      > a new card for the SWTP 680 systems to do this, so what about he s-
      100
      > systems?)
      >
      > Larry@u...
    • Larry T.
      Actually, most of the controllers for 8 drives that I know were soft sector. Only the original MITS and ICOM controllers were for hard sector media. And
      Message 2 of 3 , May 21, 2003
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        Actually, most of the controllers for 8" drives that I know were soft
        sector. Only the original MITS and ICOM controllers were for hard
        sector media. And ICOM came out with a later controller that did
        support soft sector floppies.

        As for capacities, the 8" media ran from 128Kb to 1Mb depending on
        density (1x, 2x, 4x) and # of sides (1 or 2).

        The early 5-1/4" drives started at 40Kb and worked their way up. I
        do not recall standard 360Kb on the s-100 systems, that was the
        starting point for the PC. However, Micropolis was the first to
        offer higher capacity drives, they just wern't very reliable and they
        deffinetly we not compatible with other 5-1/4" drives.

        I'll keep looking. If nothing else, I should eventually be able to
        adapt a later Western Digital floppy controller IC to a Tarbell style
        design to get a circuit that will give me the full use of the 1.44Mb
        media. CP/M did not have any problems with media of this capacity so
        it will just be a case of making the boot floppy and boot prom.

        If I find or create something, I'll post data on it back to the group
        for everyones reference.

        --- In altaircomputerclub@yahoogroups.com, alltare <no_reply@y...>
        wrote:
        >
        > Welcome to the group.
        >
        > I haven't heard of any designs for using 3" drives. The Altair
        > software and hardware was all designed around "hard-sectored"
        > diskettes, and that may prove to be the biggest problem. I have
        > never seen a hard-sectored 3" diskette- only soft-sectored.
        >
        > Of course, there were many other S-100 systems that did use soft
        > sectoring, It might be a fairly simple task to do some timing
        > changes on one of those old controllers for use with 3" disks. I
        > don't know the rotational speed of 3" drives, but I think 8" and 5"
        > ran at 360 and 300 RPM. Whatever the speeds, though, you would
        have
        > to compensate for rotational speed differences by making timing
        > changes to the circuits that generate the sector and byte timing.
        I
        > could be full of beans here, but this approach doesn't immediately
        > seem like it would be a major task. What do you other members
        think
        > about this?
        >
        > Done this simply, you wouldn't be able to use the 3" to its full
        > 1.4MB capacity. You would still only use as many tracks as the
        > original system, and as many bytes per track as the original
        system,
        > and most likely only one side of each disk. There would be a lot
        of
        > wasted potential, but at least you would be using "state-of-the-
        art"
        > diskettes and drives (or maybe not so state-of-the-art. I just
        read
        > that Dell will discontinue installing floppies on most future
        systems
        > in favor of CDs). I recall that an 8" floppy back then held 320 to
        > 360 KB on about 80 tracks. I think 5" floppies held about half
        that
        > much data per side on half as many tracks. It's been a long time,
        > so don't take any of my numbers too literally, but I think I'm in
        the
        > right ball park.
        >
        > What I would like to see is a CD burner that could be used in an
        > Altair system, using Altair BASIC, that looked to the system like
        its
        > own hard drive or floppy drive (now THERE'S a waste of space). All
        > of that old software is rotting away on 25 year old diskettes and
        > really needs to be archived on the more permanent CD medium. If
        you
        > ever see anything like that, please tell us about it.
        >
        > I look forward to seeing your pictures.
        >
        > Steve
        > ============================
        >
        > --- In altaircomputerclub@yahoogroups.com, "Larry Troth"
        <larry@u...>
        > wrote:
        > > Hello
        > >
        > > I have just joined the group and I am looking forward to gaining
        > some new
        > > knowledge regarding the old hardware that I have. After 20+
        years
        > in
        > > storage, I will finally be able to get my s-100 systems (yes, I
        have
        > > several) bake in operation. As I get them up I'll post pictures
        > and info.
        > >
        > > My question is about some new hardware for these old systems.
        > While I have
        > > a good supply of 8" floppy drives and floppies, it is only a
        matter
        > of time
        > > till the last of them give up the ghost. Has anyone come up with
        a
        > > kit/board/schematic/??? to allow the use of the new 1.44Mb 3-1/2"
        > diskette
        > > drives with these old systems? I would love to transfer my old
        > data from
        > > the 8" media to the 3-1/2" media. Does anyone know of any web
        > pages that
        > > discuss this? Are there any resources out there? (I found a
        site
        > that has
        > > a new card for the SWTP 680 systems to do this, so what about he
        s-
        > 100
        > > systems?)
        > >
        > > Larry@u...
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