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Re: [Altair Computer Club] Re: 8-inch calibration diskette source

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  • akessel@aol.com
    I have one of these disks - Its a dysan alignment disk no. mb452 pertec part number 600202-02 Cats eye at track 38 burst at tracks 01 and 76 I did my drives a
    Message 1 of 31 , Oct 5, 2005
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      I have one of these disks - Its a dysan alignment disk no. mb452
      pertec part number 600202-02
      Cats eye at track 38
      burst at tracks 01 and 76

      I did my drives a few years ago - tricky to say the list and have some notes
      on how to do it, if this will help.

      I guess with some trepidation I would lend the alignment disk to get you
      going. We altarians have to stick together.

      I have a tek 465 I bought for the job, and have instructions related to it.

      Here are my lengthy notes:

      1) Take disk out of drive note orientation of plug

      2) Start with adjusting the doors, if the cone starts of lift at about 5/8
      inch open - it should be okay.

      Else, loosen 4 allen screws with 7/64ths wrench. puch cone bar assembly
      as far as it will go to left (less than an inch) mark with a pencil on other
      side. Move to right and pencil mark on left - then center between the marks.

      Cone should be down. Open door 5/8 inch and tighten allen screws while
      holding cone down.. You should be done. With door closed hold down cone and
      suport clamp lift at end with a force meauring device, it should start to
      budge at between 6 and 9 lbs pressure. Adjust if necessary.

      3) Disk drive alignment - note this is a bit of an art.

      Hook up drive to 8800, enter the disk exerciser program starting at 0.
      Then examine 0 and run.
      Sense witches control the Drive
      A15 - loads and unloads the head (up unloads, down loads)
      A8 - A14 select track in binary - Important tracks are:
      0 - 000/000/0
      1 - 000/000/1
      38 - 010/011/0
      76 - 100/110/0

      Leave disk unloaded at track 0 for now.

      4) On a tek 465 Oscilloscope, set up channel 1 and channel 2 - Add, Inverse,
      AC - center each on screen - set vert/div to .2m for starters.

      5) hook up sync a, set up for normal sync and plan to play with level and
      slope.

      Follow directions in computer notes article. - but with these notes here:

      Put drive on side top facing you and step motor on right (connector on
      right). attach probes per article and pc board on drive. Best to put drive on
      two books or something so it will stay cool - don't just leave on a desk.

      Go to track 38 and do CE adjustment. Loosen all 4 bolts/screws on the step
      motor (rear). Set Horiz/Div 2 or three steps short of full clockwise (50m I
      think) look for a wave form similar to article, adjust to view wave form
      better as well adjust vert/div if necessary. You may have to adjust slope and
      level to view better, try level on left setting. Turn screw away slightly and
      towards you slightly, note which makes the wave form closer to symetric. If
      you have to turn away from you, you need to move motor to back, if you have
      to turn towards you, move motor to front. Take a wood block (kids play blocks
      work great) hold against solid part of motor and whack with a good hammer to
      make wave symetric. Tighten the front left screw for now.

      Insert ce disk: go to track 0 , then track 1, load head. change horiz/div to
      20u or 50 u play with slope until you see a burst - note doesn't look quite
      like the burst in the article, but kind of obvious none the less - The burst
      jumps around. Adjust horzi/div for best view. move to track 76 and observe
      same. if you can't see any bursts adjust the index sensor. This sits at the
      very front of the drive and looks for those little index holes in the
      floppy. There is a bracket with two screws/bolts - the bolts have nuts at
      underside of drive - holds the hub motor in place - loosen slightly (you need to take
      out disk - so unload first). adjust index, reinsert disk, load and look
      again - play with this until you see a burst and try to make so one shows up at
      the beginning (left) of the trace. Watch for second burst after the first -
      should be about 4 grids away at 20u and 2 grids away at 50u. Now go to other
      end at track 76 to 1 or 1 to 76 and look again. You want to see roughly the
      same pattern. YOu can move the step motor back by inserting a screw driver
      between the motor and the frame and can move the back either side to side,
      thus adjusting the way the screw runs out as the head moves from track 1 to 76.
      It needs to move out straight. This is the art part. Do the best you can,
      recheck the Cats eye occassionally, in case you mess that up and go back and
      forth until you can roughly see similar patterns on 1 and 76. That should do
      it. try to boot from a basic disk and if it works you are okay.

      What fun, I sweat just thinking about it.

      Andy Kessel


      [Non-text portions of this message have been removed]
    • Andrew Kessel
      That s correct. On my computer that has the rom basic board, I can just upload the basic program as if it were being typed by the terminal. So I guess I am
      Message 31 of 31 , Oct 7, 2005
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        That's correct. On my computer that has the rom basic board, I can just
        upload the basic program as if it were being typed by the terminal.
        So I guess I am just emulating a terminal doing manual entry.

        On 10/7/05, H.E.Robert <ueoguy@...> wrote:
        >
        > Steve,
        >
        > Andy and I went round and round on this a while back, and I think what
        > he is doing is via
        > the "special monitor eprom", he uploads a memory image of anything,
        > Altair DOS, Disk Extended BASIC,
        > whatever, through the serial port, and then runs from the octal "0"
        > location. Just the same as using paper tape,
        > or audio tape, just without the checksum! He can make changes to the
        > image in RAM, then using a small program, he writes the image back out
        > to his PDA as an ascii file. So in the case of disk BASIC, if you have
        > drives connected, they will work, if you don't, it locks up....Just a
        > you would expect a Micro-Soft product to do! O:-)
        >
        > Just Bob!
        >
        > Steve wrote:
        >
        > >So Andy, you're using your PDA through an RS232 port, and pretending
        > >that you have a cassette system? And running Cassette BASIC, I
        > >guess?
        > >
        > >steve
        > >==============================
        > >
        > >--- In altaircomputerclub@yahoogroups.com, Andrew Kessel
        > ><akessel56@g...> wrote:
        > >
        > >
        > >>One other thought on this subject. I found it worked pretty well to
        > >>
        > >>
        > >use a
        > >
        > >
        > >>pda (like a palm) and a serial cable with Steve's Monitor Rom to
        > >>
        > >>
        > >both load
        > >
        > >
        > >>basic and basic software - you don't need monitor rom if you have
        > >>
        > >>
        > >basic
        > >
        > >
        > >>loaded as the basic program will just load in.
        > >> A little nicer than using a computer, not so nice as a some kind
        > >>
        > >>
        > >of Altair
        > >
        > >
        > >>Flash Drive which would be really pretty cool. Note that if the
        > >>
        > >>
        > >parallel
        > >
        > >
        > >>port io is possible it might not be that tough to right a driver to
        > >>
        > >>
        > >get a
        > >
        > >
        > >>parallel port drive like an old zip drive to work - just a thought.
        > >>
        > >> On 10/6/05, Steve <alltare@y...> wrote:
        > >>
        > >>
        > >>>Craig, Bob-
        > >>>
        > >>>I'm not stuck on any particular storage medium, but I think I
        > >>>
        > >>>
        > >would
        > >
        > >
        > >>>prefer solid state rather than spinning state. I'm just throwing
        > >>>
        > >>>
        > >out
        > >
        > >
        > >>>ideas and things to consider. I was mostly explaining before that
        > >>>the software (Altair BASIC) may not be able to run as fast as the
        > >>>storage device is capable of, so no matter what medium we use,
        > >>>
        > >>>
        > >we'll
        > >
        > >
        > >>>have to slow it down, via the handshake signals, so that the
        > >>>
        > >>>
        > >computer
        > >
        > >
        > >>>can talk to it. I think we're really thinking along the same
        > >>>
        > >>>
        > >lines,
        > >
        > >
        > >>>but saying them in different ways.
        > >>>
        > >>>Having the controller talk to an original drive in addition to our
        > >>>new fake drive(s) would be a good idea, Bob, and all the new stuff
        > >>>could be easily tucked into a corner of a DCDD's cabinet. Or
        > >>>
        > >>>
        > >inside
        > >
        > >
        > >>>the Altair if a real drive isn't needed.
        > >>>
        > >>>The Altair hard disk system used a standard 4PIO board (octal 240
        > >>>thru 247) as the computer's interface. The 4PIO connected to an
        > >>>external HD controller that used the same cabinet as a DCDD single
        > >>>floppy drive. There were 3 big logic boards in that cabinet. The
        > >>>controller box was in turn connected to a Pertec 2-platter or 4-
        > >>>platter 14" hard drive through 2 ~50-conductor ribbon cables. Each
        > >>>platter held 5MB.
        > >>>
        > >>>Except for the added code to support the hard disk, the BASIC
        > >>>software was exactly the same as floppy disk BASIC. I can't think
        > >>>
        > >>>
        > >of
        > >
        > >
        > >>>any good reason to try to make a hard disk substitute- it would
        > >>>
        > >>>
        > >turn
        > >
        > >
        > >>>out to be a bucket of worms, I'll bet.
        > >>>
        > >>>steve
        > >>>========================
        > >>>--- In altaircomputerclub@yahoogroups.com, "H.E.Robert"
        > >>>
        > >>>
        > ><ueoguy@y...>
        > >
        > >
        > >>>wrote:
        > >>>
        > >>>
        > >>>>Steve, Craig,
        > >>>>
        > >>>>I like what I see, a really great discussion on the
        > >>>>
        > >>>>
        > >possibilities,
        > >
        > >
        > >>>>certainly gone beyond my
        > >>>>original concept. I can also understand the desire to replace
        > >>>>
        > >>>>
        > >the
        > >
        > >
        > >>>>original controller cards.
        > >>>>
        > >>>>My original thought was to "talk" to the original controllers,
        > >>>>
        > >>>>
        > >so
        > >
        > >
        > >>>that
        > >>>
        > >>>
        > >>>>you could "mix" the original
        > >>>>drives and media with the new and improved media, allowing
        > >>>>
        > >>>>
        > >copying
        > >
        > >
        > >>>from
        > >>>
        > >>>
        > >>>>one type of media
        > >>>>to the other, and back.
        > >>>>
        > >>>>So my hypothetical question, is would it be possible to connect
        > >>>>
        > >>>>
        > >at
        > >
        > >
        > >>>least
        > >>>
        > >>>
        > >>>>one original drive, and
        > >>>>to really push the envelope, make it either an 8" or 5.25"
        > >>>>
        > >>>>
        > >drive to
        > >
        > >
        > >>>the
        > >>>
        > >>>
        > >>>>new controller replacement
        > >>>>for copy/archive capabilities? My concern would be to maintain
        > >>>>continued use of either device
        > >>>>going into the future, and not limiting future Altair use to
        > >>>>
        > >>>>
        > >just
        > >
        > >
        > >>>the
        > >>>
        > >>>
        > >>>>new technology.
        > >>>>
        > >>>>I just thought that, a replacement "controller" might be able to
        > >>>>
        > >>>>
        > >>>support
        > >>>
        > >>>
        > >>>>both old and new devices?
        > >>>>
        > >>>>Just Bob!.......just my...."why is there no "cents" symbol on a
        > >>>>
        > >>>>
        > >pc
        > >
        > >
        > >>>>keyboard?" 1.5 cents!
        > >>>>
        > >>>>Steve wrote:
        > >>>>
        > >>>>
        > >>>>
        > >>>>>Craig,
        > >>>>>
        > >>>>>Wouldn't it be great to use your iPod as the storage device?
        > >>>>>
        > >>>>>The new controller card would have to simulate all of the
        > >>>>>
        > >>>>>
        > >signals
        > >
        > >
        > >>>>>that normally come from the real thing. I don't see any big
        > >>>>>
        > >>>>>
        > >>>problems
        > >>>
        > >>>
        > >>>>>with drive selection- The drive select commands are really just
        > >>>>>address specifiers, just like PCs today. The controller would
        > >>>>>
        > >>>>>
        > >>>select
        > >>>
        > >>>
        > >>>>>and load from whatever part of the flash drive or hard disk
        > >>>>>
        > >>>>>
        > >that
        > >
        > >
        > >>>you
        > >>>
        > >>>
        > >>>>>have addressed as drive 2. It's just another addressing
        > >>>>>
        > >>>>>
        > >>>function.
        > >>>
        > >>>
        > >>>>>There's sector addressing, track (cylinder) addressing, and
        > >>>>>
        > >>>>>
        > >drive
        > >
        > >
        > >>>>>addressing.
        > >>>>>
        > >>>>>I think the most critical part (but not all that difficult)
        > >>>>>
        > >>>>>
        > >would
        > >
        > >
        > >>>be
        > >>>
        > >>>
        > >>>>>to simulate all of the time-dependent handshake signals. For
        > >>>>>example, after a head step command, a delay must be generated
        > >>>>>
        > >>>>>
        > >to
        > >
        > >
        > >>>>>allow the head to actually get to the next track before other
        > >>>>>commands can be accepted. This kind of "clear to send" signal
        > >>>>>
        > >>>>>
        > >is
        > >
        > >
        > >>>>>what most of those one-shot timer circuits are for.
        > >>>>>
        > >>>>>Some commands can simply be ignored, like the HEAD CURRENT
        > >>>>>
        > >>>>>
        > >switch
        > >
        > >
        > >>>and
        > >>>
        > >>>
        > >>>>>TRIM ERASE.
        > >>>>>
        > >>>>>Although any modern medium will have much faster access time
        > >>>>>
        > >>>>>
        > >than
        > >
        > >
        > >>>the
        > >>>
        > >>>
        > >>>>>FD400/500 drive, we may not be able to make much use of that
        > >>>>>
        > >>>>>
        > >>>speed.
        > >>>
        > >>>
        > >>>>>I suspect that if we speeded up the track step delay or head
        > >>>>>
        > >>>>>
        > >load
        > >
        > >
        > >>>>>settle time, etc., the poor old 8080 and interpreter BASIC
        > >>>>>
        > >>>>>
        > >might
        > >
        > >
        > >>>not
        > >>>
        > >>>
        > >>>>>be able to keep up. But who cares, really?
        > >>>>>
        > >>>>>This has all been discused before, a little bit, but a quick
        > >>>>>
        > >>>>>
        > >>>search
        > >>>
        > >>>
        > >>>>>couldn't find the relevant messages in the archives.
        > >>>>>
        > >>>>>steve
        > >>>>>=========================================
        > >>>>>
        > >>>>>--- In altaircomputerclub@yahoogroups.com, Craig Landrum
        > >>>>><craigl@m...> wrote:
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>>>...snip...
        > >>>>>>>I agree with you, JustBob. A trouble-free floppy disk
        > >>>>>>>
        > >>>>>>>
        > >>>replacement
        > >>>
        > >>>
        > >>>>>>>would be very useful. I would be very happy if I could get
        > >>>>>>>
        > >>>>>>>
        > >rid
        > >
        > >
        > >>>of
        > >>>
        > >>>
        > >>>>>>>the MITS controllers and Pertec floppy, and replace them
        > >>>>>>>
        > >>>>>>>
        > >with a
        > >
        > >
        > >>>>>>>
        > >>>>>>>
        > >>>>>plug-
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>>>in replacement controller that used a 3.5" floppy, or a
        > >>>>>>>
        > >>>>>>>
        > >modern
        > >
        > >
        > >>>>>>>
        > >>>>>>>
        > >>>>>hard
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>>>drive, or better yet, solid-state media such as a Compact
        > >>>>>>>
        > >>>>>>>
        > >Flash
        > >
        > >
        > >>>>>>>
        > >>>>>>>
        > >>>>>card
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>>>or USB thumb drive.
        > >>>>>>>
        > >>>>>>>The entirety of all of MITS' software (BASIC, DOS, all the
        > >>>>>>>
        > >>>>>>>
        > >>>>>>>
        > >>>>>>>
        > >>>>>business
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>>>software, ...) would fit on one 5MB hard disk platter with
        > >>>>>>>
        > >>>>>>>
        > >room
        > >
        > >
        > >>>to
        > >>>
        > >>>
        > >>>>>>>spare, so even the smallest of today's hard drives would be
        > >>>>>>>
        > >>>>>>>
        > >big
        > >
        > >
        > >>>>>>>enough for any conveivable storage requirements.
        > >>>>>>>
        > >>>>>>>In case you guys weren't aware of it, Altair floppies didn't
        > >>>>>>>
        > >>>>>>>
        > >use
        > >
        > >
        > >>>>>>>
        > >>>>>>>
        > >>>>>DMA
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>>>or any other tricky schemes for floppy I/O. Everything worked
        > >>>>>>>through just 3 standard I/O ports (octal 10, 11, & 12). Most
        > >>>>>>>
        > >>>>>>>
        > >of
        > >
        > >
        > >>>>>>>
        > >>>>>>>
        > >>>>>the
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>>>housekeeping and control was built into BASIC, so most of the
        > >>>>>>>hardware between the Altair's buss and the floppy drive was
        > >>>>>>>
        > >>>>>>>
        > >just
        > >
        > >
        > >>>>>>>
        > >>>>>>>
        > >>>>>for
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>
        > >>>>>>>timing or signal conditioning and buffering.
        > >>>>>>>
        > >>>>>>>steve
        > >>>>>>>
        > >>>>>>>
        > >>>>>>>
        > >>>>>>>
        > >>>>>>Hmmmm - now this is an interesting problem. Ideally you
        > >>>>>>
        > >>>>>>
        > >should be
        > >
        > >
        > >>>>>>able to remove the MITS controller and drives, plug in the
        > >>>>>>replacement card and have it work exactly like the floppies.
        > >>>>>>The only problem I see is how to tell the board which "disk"
        > >>>>>>is mounted in which "drive". Because the board has to
        > >>>>>>act *exactly* like a MITS floppy controller in order to be
        > >>>>>>fully compatible with all the software, it would have to
        > >>>>>>react properly to commands to ports 10,11, and 12. The
        > >>>>>>emulated "disks" would need to be the same size as MITS
        > >>>>>>disks. The ability to specify which "disk" is to "inserted"
        > >>>>>>in which "drive" is the hard part. My first take would
        > >>>>>>be to have an internal board that emulates the controller,
        > >>>>>>with a USB connection to the backplane. This would be
        > >>>>>>connected to an external box with a small LCD screen and
        > >>>>>>a few buttons, with a port to plug in the media (assume
        > >>>>>>its a USB thumbdrive). The user would hook up the
        > >>>>>>thumbdrive to their PC and create as many blank *disks*
        > >>>>>>as they want. Each *disk* would be a binary file of
        > >>>>>>the exact capacity of a hard sectored floppy. A blank
        > >>>>>>file of this type is copied to the thumb drive for each
        > >>>>>>disk desired and named whatever they wish, such as
        > >>>>>>"Altair DOS 1.1" or "Altair Basic 5.0", etc. Now that
        > >>>>>>the drive has been loaded with a number of blank
        > >>>>>>"floppies", it is removed from the PC and plugged into
        > >>>>>>the external emulator box. The box examines the
        > >>>>>>thumbdrive and puts the names of all the "floppy" files
        > >>>>>>onto the LCD. Using the minimal box controls, the user
        > >>>>>>then scrolls up or down and selects the desired "floppy"
        > >>>>>>to be mounted in a "drive" (drive 0,1,etc). Once this
        > >>>>>>has occured, we are in business and from that point its
        > >>>>>>a simple matter to service drive enable/head load/seek/
        > >>>>>>read and write commands from the internal board.
        > >>>>>>
        > >>>>>>I'd love to design and build this thing. If done right,
        > >>>>>>it could emulate other floppy controllers and could
        > >>>>>>be used in other machines such as an IMSAI, etc.
        > >>>>>>
        > >>>>>>It would also greatly simplify the exchange of disks
        > >>>>>>among people such as ourselves - just plug the thumb
        > >>>>>>drive back into your PC and email a binary diskette to
        > >>>>>>someone who then puts in on their thumbdrive, etc.
        > >>>>>>
        > >>>>>>I know this could be even simpler, but it would be much
        > >>>>>>less flexible - i.e. you could emulate 15 drives with
        > >>>>>>a fixed floppy mounted on each and simply not allow
        > >>>>>>the emulated floppies to be removed from the drive.
        > >>>>>>That type of solution could all be done on a single
        > >>>>>>board with some flash memory but you would be
        > >>>>>>limited to whatever could be held on 15 diskettes and
        > >>>>>>you would have to live with booting from whatever is
        > >>>>>>floppy is defined as being drive 0.
        > >>>>>>
        > >>>>>>What do you guys think about all this? A couple of
        > >>>>>>PIC chips, some minor logic, an LCD screen, and we'd
        > >>>>>>be in business.
        > >>>>>>
        > >>>>>>I may take a whack at this or would be willing to do
        > >>>>>>the software part in collaboration with a h/w guy.
        > >>>>>>
        > >>>>>>--
        > >>>>>>Craig Landrum
        > >>>>>>
        > >>>>>>
        > >>>
        > >>>
        > >>>
        > >>>
        > >>>---- SPECIAL NOTICE CONCERNING "SPAM" ----
        > >>>If this message appears to be junk mail that has nothing to do
        > >>>
        > >>>
        > >with our
        > >
        > >
        > >>>group, there are things you can do to prevent receiving more of
        > >>>
        > >>>
        > >the same. Go
        > >
        > >
        > >>>to our Yahoo group's website, sign in, open the FILES folder, and
        > >>>
        > >>>
        > >read the
        > >
        > >
        > >>>text file called "Blocking Spam" for infomation about your
        > >>>
        > >>>
        > >options.
        > >
        > >
        > >>>--- Steve, your group moderator
        > >>>
        > >>>Yahoo! Groups Links
        > >>>
        > >>>
        > >>>
        > >>>
        > >>>
        > >>>
        > >>>
        > >>>
        > >>>
        > >>>
        > >>--
        > >>Andrew Kessel
        > >>
        > >>
        > >>[Non-text portions of this message have been removed]
        > >>
        > >>
        > >>
        > >
        > >
        > >
        > >
        > >
        > >
        > >
        > >---- SPECIAL NOTICE CONCERNING "SPAM" ----
        > >If this message appears to be junk mail that has nothing to do with our
        > group, there are things you can do to prevent receiving more of the same. Go
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        > text file called "Blocking Spam" for infomation about your options.
        > >--- Steve, your group moderator
        > >
        > >Yahoo! Groups Links
        > >
        > >
        > >
        > >
        > >
        > >
        > >
        > >
        > >
        > >
        > >
        >
        >
        >
        >
        > ---- SPECIAL NOTICE CONCERNING "SPAM" ----
        > If this message appears to be junk mail that has nothing to do with our
        > group, there are things you can do to prevent receiving more of the same. Go
        > to our Yahoo group's website, sign in, open the FILES folder, and read the
        > text file called "Blocking Spam" for infomation about your options.
        > --- Steve, your group moderator
        >
        > Yahoo! Groups Links
        >
        >
        >
        >
        >
        >
        >
        >
        >


        --
        Andrew Kessel


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