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Re: Booting a NorthStar Horizon

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  • joshbensadon
    Hi Terry, I can t help but to ask a little more about the hard sectored disks. Do they use 10 evenly spaced holes? or is 9 evenly spaced with the 10th hole
    Message 1 of 21 , Jun 2, 2012
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      Hi Terry,

      I can't help but to ask a little more about the hard sectored disks.
      Do they use 10 evenly spaced holes? or is 9 evenly spaced with the 10th hole being a double holed Sector 0 index? The question I'm trying to ask is how do they determine Sector 0?

      Thanks
      Josh



      --- In midatlanticretro@yahoogroups.com, "wb4jfi" <wb4jfi@...> wrote:
      >
      > Sorry, maybe I confused you? It does not require 10 disks. Only one drive is required to run the computer. I had two or three drives on my CP/M machines, but only one is necessary.
      >
      > There is no need to do any physical punching of disks either. Floppies are either the proper kind (10 sectors, hard sectors in your case), or they are not. I probably confused you with all the user-group disks blather. Sorry, TMI.
      >
      > More background info only:
      > The 10 sectors hard sectors means that there are ten holes in the floppy disk itself, and the disk drive uses those holes to "time" where to record or read data on the floppy medium.
      >
      > A floppy disk records the data in groups, called sectors. Several sectors are recorded in a circle around the disk media as it rotates, 360-degrees of sectors makes up a "track". Multiple tracks are then recorded from the inside of the disk media toward the outside (or vice versa). The combination of data bytes per sector, number of sectors per track, and number of tracks tells you how much total data a floppy disk media can handle (less overhead).
      >
      > Floppy disk media can be soft-sectored or hard sectored. In soft sectors, there is only one hole in the actual media, where the little hole that you can see near the center of the envelope is. AS you turn the media inside the envelope, you will see only one hole for each complete revolution. The drive uses that one hole as a reference, and times the rest of the sectors based on that once-a-revolution pulse.
      >
      > For the North Star hard-sector floppies, you will actually see ten holes in the media as you spin it inside the envelope for 360 degrees. The electronics uses those holes to "time" when to start each sector of data.
      >
      > Hard sectoring is easier to design support electronic for, but limits you to the number of sector holes punched into the media. With soft sectoring, you can design the electronics to support as many sectors of data as you want, up to the recording limit of the media.
      > end of background info...
      >
      > The Horizon and CP/M will require some learning. Do you have a serial terminal to use as well? The Horizon was an S-100 bus computer, often in a nice wood box. It used an RS-232 serial connection to a "terminal", probably at 9600 baud. For example, I used mostly Heathkit H-19 video terminals. I still have two H-19s, and a couple of Altairs and IMSAIs that I can get running if pressed, but none are compatible with North Star hard-sectoring.
      >
      > The biggest issue as far as getting your hardware running is probably the disk drives. Over time, the head positioning motor and mechanism usually freezes, especially on older Shuggart drives. You might look at what make/model the floppy drives are, and look on the Internet for more info. I used Shuggart SA-400 and SA-450(?) drives on my North Star, and Shuggart SA-800 drives on my other CP/M systems. I have about ten SA-800 drives, and every once in a while, I manually move the head mechanism to keep them limber. I had to dump some other drives after they froze, and I could not get them to move anymore.
      >
      > As someone else said, do some Internet research on North Star, Horizon computers, CP/M, and your particular drives. That time will be well-spent.
      >
      > CP/M systems are fun to get working, and are an early part of the microcomputer history. If you like older stuff, it is definately worth investing time to get running. But, other than the original Adventure or Dungeons, don't plan to play many games on them.
      >
      > Good luck.
      > Terry
      >
      > (ps: I can be reached directly at tfox@..., and live in Charleston, SC. Used to be in DC area for many years).
      >
      > --- In midatlanticretro@yahoogroups.com, Kyle Owen <kylevowen@> wrote:
      > >
      > > Well, this all sounds much more daunting than I had hoped.
      > >
      > > Why are 10 disks required? I can envision that one would be used to
      > > actually boot the machine to a usable state, with some basic monitor, but
      > > what would the other 9 do?
      > >
      > > Terry, I might have to take you up on your kind offer. It'd be good to see
      > > if the machine even boots. Considering I have no experience with CP/M,
      > > what'll it take to redo the disks for use in the N*?
      > >
      > > Does anyone have a set of disks they'd be willing to sell? I don't think I
      > > am capable of punching my own disks without a jig and a punch, so making my
      > > own probably won't happen.
      > >
      > > Kyle
      > >
      > > On Sat, Jun 2, 2012 at 3:02 PM, wb4jfi <wb4jfi@> wrote:
      > >
      > > > **
      > > >
      > > >
      > > > As a follow-up, I found and opened my box of N* floppies.
      > > >
      > > > I have an original N* disk unlabeled what it is, an N* original MDS-DQ
      > > > release 5.1 (1979), MDS Release 4 (1978), N* DOS Version 2 & North Star
      > > > Basic Version 6 Release 3. These are all "North Star Computers" originals.
      > > >
      > > > I also have disks with CP/M 1.4 and 2.2 on them, but mostly for an Altair
      > > > or IMSAI computer with the N* floppy controller. You would have to redo
      > > > them for the Horizon. Break out your CP/M manuals and look at movecpm,
      > > > stat, pip,and ddt.
      > > >
      > > > N* controllers did single-density, double-density, and apparently "high
      > > > density". Most of my floppies are single or double density. Also, single
      > > > and double sided.
      > > >
      > > > I also have copies of the old North Star User Group disks 1-20, many
      > > > CP/M-UG and SIG/M-UG disks. Back then, a lot of us "punched" another set of
      > > > sector read holes in the floppies, so both sides could be used. Most of
      > > > these User Group disks are punched, so there are two user-group disks to
      > > > each floopy. Totally unknown if they are readable now!
      > > >
      > > > Anyway, if you are interested, I could probably ship some/all to you to
      > > > try out. Sorry that I do not have an orignal Horizon disk.
      > > > Terry, WB4JFI
      > > >
      > > >
      > > > --- In midatlanticretro@yahoogroups.com, "wb4jfi" <wb4jfi@> wrote:
      > > > >
      > > > > Yes, the North Star floppy was 5.25-inch, hard-sector, ten sectors, I
      > > > think. I did not have a Horizon, but I used the North Star floppy disk
      > > > controller and SA-400 drives on a few computers, including the AMRAD CBBS.
      > > > >
      > > > > The main OS was CP/M. I used CP/M 1.4 and 2.2. I had MP/M, but never got
      > > > it running on the North Star system, just an IMSAI and Tarbell controller.
      > > > >
      > > > > I still have most of my North Star floppies in a box somewhere. I'm sure
      > > > that I have some origina disks, plus a few blank hard-sector ones. I'm not
      > > > sure what condition they are in, as the box has not been cracked open in 15
      > > > or so years. But, they have always been in a climate-controlled room.
      > > > >
      > > > > I can look for the box and report back.
      > > > > Terry, WB4JFI
      > > > >
      > > > > --- In midatlanticretro@yahoogroups.com, Mike Loewen <mloewen@> wrote:
      > > > > >
      > > > > > On Fri, 1 Jun 2012, Kyle Owen wrote:
      > > > > >
      > > > > > > Are the floppies anything special? I assume they're soft-sectored,
      > > > probably
      > > > > > > single-density single-sided, right? If so, I think I would have very
      > > > little
      > > > > > > trouble making boot disks from a MS-DOS machine.
      > > > > >
      > > > > > Don't assume they're soft-sectored. The original Horizon used
      > > > > > hard-sectored (10 sector/track) diskettes. You should do a little
      > > > > > research to figure out which controller you have.
      > > > > >
      > > > > >
      > > > > > Mike Loewen mloewen@
      > > > > > Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
      > > > > >
      > > > >
      > > >
      > > >
      > > >
      > >
      >
    • Kyle Owen
      No, you didn t confuse me; Bill D. said, Do some searching on Northstar Horizon disk controllers and in general Northstar DOS. You need 10 hard-sectored
      Message 2 of 21 , Jun 2, 2012
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        No, you didn't confuse me; Bill D. said, "Do some searching on Northstar Horizon disk controllers and in general Northstar DOS.  You need 10 hard-sectored disks." A bit of a confusing sentence, that last one. :)

        I read about the punching in regards to making your own hard-sectored disks. Again, I don't have the punch or jig to properly do this, so either way, I'm going to need to buy the media eventually.

        Thank you for the very informative description of hard- versus soft-sectored media. That makes total sense, and it sounds like N* equipment would be easily bootable with soft-sectored media if the floppy controller was set up for that. I suppose the OS doesn't care, just the controller. 

        I do have a serial terminal (Zenith Z-29 and my laptop with GNU's 'screen'), so talking to it is no problem. I'm all for getting it working; it certainly wouldn't be the first old system I've rejuvenated, and definitely won't be the last! I don't have it right next to me (it's actually at the university's amateur radio club room), so I can confirm the floppy drive models, but they do appear original to the unit. When I powered it up, the spindle motors did spin up, but I have not yet checked if the heads will move.

        Thanks again for all of the great info!

        73,

        Kyle

        On Sat, Jun 2, 2012 at 6:47 PM, wb4jfi <wb4jfi@...> wrote:
         

        Sorry, maybe I confused you? It does not require 10 disks. Only one drive is required to run the computer. I had two or three drives on my CP/M machines, but only one is necessary.

        There is no need to do any physical punching of disks either. Floppies are either the proper kind (10 sectors, hard sectors in your case), or they are not. I probably confused you with all the user-group disks blather. Sorry, TMI.

        More background info only:
        The 10 sectors hard sectors means that there are ten holes in the floppy disk itself, and the disk drive uses those holes to "time" where to record or read data on the floppy medium.

        A floppy disk records the data in groups, called sectors. Several sectors are recorded in a circle around the disk media as it rotates, 360-degrees of sectors makes up a "track". Multiple tracks are then recorded from the inside of the disk media toward the outside (or vice versa). The combination of data bytes per sector, number of sectors per track, and number of tracks tells you how much total data a floppy disk media can handle (less overhead).

        Floppy disk media can be soft-sectored or hard sectored. In soft sectors, there is only one hole in the actual media, where the little hole that you can see near the center of the envelope is. AS you turn the media inside the envelope, you will see only one hole for each complete revolution. The drive uses that one hole as a reference, and times the rest of the sectors based on that once-a-revolution pulse.

        For the North Star hard-sector floppies, you will actually see ten holes in the media as you spin it inside the envelope for 360 degrees. The electronics uses those holes to "time" when to start each sector of data.

        Hard sectoring is easier to design support electronic for, but limits you to the number of sector holes punched into the media. With soft sectoring, you can design the electronics to support as many sectors of data as you want, up to the recording limit of the media.
        end of background info...

        The Horizon and CP/M will require some learning. Do you have a serial terminal to use as well? The Horizon was an S-100 bus computer, often in a nice wood box. It used an RS-232 serial connection to a "terminal", probably at 9600 baud. For example, I used mostly Heathkit H-19 video terminals. I still have two H-19s, and a couple of Altairs and IMSAIs that I can get running if pressed, but none are compatible with North Star hard-sectoring.

        The biggest issue as far as getting your hardware running is probably the disk drives. Over time, the head positioning motor and mechanism usually freezes, especially on older Shuggart drives. You might look at what make/model the floppy drives are, and look on the Internet for more info. I used Shuggart SA-400 and SA-450(?) drives on my North Star, and Shuggart SA-800 drives on my other CP/M systems. I have about ten SA-800 drives, and every once in a while, I manually move the head mechanism to keep them limber. I had to dump some other drives after they froze, and I could not get them to move anymore.

        As someone else said, do some Internet research on North Star, Horizon computers, CP/M, and your particular drives. That time will be well-spent.

        CP/M systems are fun to get working, and are an early part of the microcomputer history. If you like older stuff, it is definately worth investing time to get running. But, other than the original Adventure or Dungeons, don't plan to play many games on them.

        Good luck.
        Terry

        (ps: I can be reached directly at tfox@..., and live in Charleston, SC. Used to be in DC area for many years).



        --- In midatlanticretro@yahoogroups.com, Kyle Owen <kylevowen@...> wrote:
        >
        > Well, this all sounds much more daunting than I had hoped.
        >
        > Why are 10 disks required? I can envision that one would be used to
        > actually boot the machine to a usable state, with some basic monitor, but
        > what would the other 9 do?
        >
        > Terry, I might have to take you up on your kind offer. It'd be good to see
        > if the machine even boots. Considering I have no experience with CP/M,
        > what'll it take to redo the disks for use in the N*?
        >
        > Does anyone have a set of disks they'd be willing to sell? I don't think I
        > am capable of punching my own disks without a jig and a punch, so making my
        > own probably won't happen.
        >
        > Kyle
        >
        > On Sat, Jun 2, 2012 at 3:02 PM, wb4jfi <wb4jfi@...> wrote:
        >
        > > **

        > >
        > >
        > > As a follow-up, I found and opened my box of N* floppies.
        > >
        > > I have an original N* disk unlabeled what it is, an N* original MDS-DQ
        > > release 5.1 (1979), MDS Release 4 (1978), N* DOS Version 2 & North Star
        > > Basic Version 6 Release 3. These are all "North Star Computers" originals.
        > >
        > > I also have disks with CP/M 1.4 and 2.2 on them, but mostly for an Altair
        > > or IMSAI computer with the N* floppy controller. You would have to redo
        > > them for the Horizon. Break out your CP/M manuals and look at movecpm,
        > > stat, pip,and ddt.
        > >
        > > N* controllers did single-density, double-density, and apparently "high
        > > density". Most of my floppies are single or double density. Also, single
        > > and double sided.
        > >
        > > I also have copies of the old North Star User Group disks 1-20, many
        > > CP/M-UG and SIG/M-UG disks. Back then, a lot of us "punched" another set of
        > > sector read holes in the floppies, so both sides could be used. Most of
        > > these User Group disks are punched, so there are two user-group disks to
        > > each floopy. Totally unknown if they are readable now!
        > >
        > > Anyway, if you are interested, I could probably ship some/all to you to
        > > try out. Sorry that I do not have an orignal Horizon disk.
        > > Terry, WB4JFI
        > >
        > >
        > > --- In midatlanticretro@yahoogroups.com, "wb4jfi" <wb4jfi@> wrote:
        > > >
        > > > Yes, the North Star floppy was 5.25-inch, hard-sector, ten sectors, I
        > > think. I did not have a Horizon, but I used the North Star floppy disk
        > > controller and SA-400 drives on a few computers, including the AMRAD CBBS.
        > > >
        > > > The main OS was CP/M. I used CP/M 1.4 and 2.2. I had MP/M, but never got
        > > it running on the North Star system, just an IMSAI and Tarbell controller.
        > > >
        > > > I still have most of my North Star floppies in a box somewhere. I'm sure
        > > that I have some origina disks, plus a few blank hard-sector ones. I'm not
        > > sure what condition they are in, as the box has not been cracked open in 15
        > > or so years. But, they have always been in a climate-controlled room.
        > > >
        > > > I can look for the box and report back.
        > > > Terry, WB4JFI
        > > >
        > > > --- In midatlanticretro@yahoogroups.com, Mike Loewen <mloewen@> wrote:
        > > > >
        > > > > On Fri, 1 Jun 2012, Kyle Owen wrote:
        > > > >
        > > > > > Are the floppies anything special? I assume they're soft-sectored,
        > > probably
        > > > > > single-density single-sided, right? If so, I think I would have very
        > > little
        > > > > > trouble making boot disks from a MS-DOS machine.
        > > > >
        > > > > Don't assume they're soft-sectored. The original Horizon used
        > > > > hard-sectored (10 sector/track) diskettes. You should do a little
        > > > > research to figure out which controller you have.
        > > > >
        > > > >
        > > > > Mike Loewen mloewen@
        > > > > Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
        > > > >
        > > >
        > >
        > >
        > >
        >


      • wb4jfi
        The ten sector holes are evenly spaced around the media. There is an eleventh hole midway between two others, I ve always assumed this is the index hole,
        Message 3 of 21 , Jun 3, 2012
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          The ten sector holes are evenly spaced around the media. There is an eleventh hole midway between two others, I've always assumed this is the "index" hole, that resets/starts the count. Somewhere I used to have a full set of docs for both the N* controller, and the SA-400 drives, but I think that did not make the last move.
          Terry


          --- In midatlanticretro@yahoogroups.com, joshbensadon <no_reply@...> wrote:
          >
          > Hi Terry,
          >
          > I can't help but to ask a little more about the hard sectored disks.
          > Do they use 10 evenly spaced holes? or is 9 evenly spaced with the 10th hole being a double holed Sector 0 index? The question I'm trying to ask is how do they determine Sector 0?
          >
          > Thanks
          > Josh
          >
          >
          <snip>
        • B Degnan
          Yes, it s the index hole used as a starting reference to id the sectors. This hole is present in both hard and soft-sectored disks.
          Message 4 of 21 , Jun 3, 2012
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            Yes, it's the index hole used as a starting reference to id the
            sectors. This hole is present in both hard and soft-sectored disks.


            At 02:12 PM 6/3/2012, you wrote:
            >The ten sector holes are evenly spaced around the media. There is
            >an eleventh hole midway between two others, I've always assumed this
            >is the "index" hole, that resets/starts the count. Somewhere I used
            >to have a full set of docs for both the N* controller, and the
            >SA-400 drives, but I think that did not make the last move.
            >Terry
            >
            >
            >--- In midatlanticretro@yahoogroups.com, joshbensadon <no_reply@...> wrote:
            > >
            > > Hi Terry,
            > >
            > > I can't help but to ask a little more about the hard sectored disks.
            > > Do they use 10 evenly spaced holes? or is 9 evenly spaced with
            > the 10th hole being a double holed Sector 0 index? The question
            > I'm trying to ask is how do they determine Sector 0?
            > >
            > > Thanks
            > > Josh
            > >
            > >
            ><snip>
            >
            >
            >
            >
            >------------------------------------
            >
            >Yahoo! Groups Links
            >
            >
            >
          • Kyle Owen
            I got a chance to look at the N* again today. It looks like the disk controller is an MDS-AD3, from N*. Also installed is a CompuKit Econoram VII A board, with
            Message 5 of 21 , Jun 4, 2012
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              I got a chance to look at the N* again today. It looks like the disk controller is an MDS-AD3, from N*. Also installed is a CompuKit Econoram VII A board, with one of the 5 of the 6 rows of RAM fully populated. There's also a N* 16k RAM board, and the processor card, a ZPB-A2. The floppy drives are made by Tandon, and are both TM101-4s. 

              I can't find too much info the particular floppy controller, other than that it appears to be a double-density unit. I suppose it's still using hard sectors. 

              73,

              Kyle
            • Mike Loewen
              ... Here s a page and a manual for the older, MDS-AD2: http://www.s100computers.com/Hardware%20Folder/Northstar/MDS/MDS.htm Mike Loewen
              Message 6 of 21 , Jun 4, 2012
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                On Mon, 4 Jun 2012, Kyle Owen wrote:

                > I got a chance to look at the N* again today. It looks like the disk
                > controller is an MDS-AD3, from N*. Also installed is a CompuKit Econoram
                > VII A board, with one of the 5 of the 6 rows of RAM fully populated.
                > There's also a N* 16k RAM board, and the processor card, a ZPB-A2. The
                > floppy drives are made by Tandon, and are both TM101-4s.
                >
                > I can't find too much info the particular floppy controller, other than
                > that it appears to be a double-density unit. I suppose it's still using
                > hard sectors.

                Here's a page and a manual for the older, MDS-AD2:

                http://www.s100computers.com/Hardware%20Folder/Northstar/MDS/MDS.htm


                Mike Loewen mloewen@...
                Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
              • B Degnan
                Kyle, check bitsavers.org for the manuals, but most important find the northstar horizon user manuals, they will tell you everything you need to know. This is
                Message 7 of 21 , Jun 4, 2012
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                  Kyle,

                  check bitsavers.org for the manuals, but most important find the northstar horizon user manuals, they will tell you everything you need to know.

                  This is a classic n* system.  You will need a 10-sector northstar DOS or Northstar CP/M disk to boot.  I assume the RAM is jumpered to be contiguous, but you need to be sure you have at least the first 24K filled contiguously.

                  Bill

                  At 08:20 PM 6/4/2012, you wrote:


                  I got a chance to look at the N* again today. It looks like the disk controller is an MDS-AD3, from N*. Also installed is a CompuKit Econoram VII A board, with one of the 5 of the 6 rows of RAM fully populated. There's also a N* 16k RAM board, and the processor card, a ZPB-A2. The floppy drives are made by Tandon, and are both TM101-4s.

                  I can't find too much info the particular floppy controller, other than that it appears to be a double-density unit. I suppose it's still using hard sectors.

                  73,

                  Kyle


                • s100doctor
                  For those who posted Herb will chime in ...I don t follow this mail list daily. If you think someone should contact me, please refer them to my Web site so
                  Message 8 of 21 , Jun 9, 2012
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                    For those who posted "Herb will chime in"...I don't follow this mail list daily. If you think someone should contact me, please refer them to my Web site so they can do that. I have a specific Web page on Northstar, for instance, that would be a good link to have offered Kyle.

                    Kyle, about your "northstar" system. With S-100 computers, you won't know what you have until you survey the cards. Now that you've done so, I can see it's mostly "Northstar".

                    Northstar made floppy controllers as their first product, then offered whole systems. The Northstar Horizon (S-100 system) was pretty popular so there's a lot of these around. Almost all Northstar stuff used "hard sectored" diskettes, as discussed, including yours. It's 10 sector holes plus an eleventh hole as the "index". Look up "hard sectored floppy" on the Web to learn what that's about. By the way, that "10" is what Bill Degnan was probably talking about, OK?

                    Kyle, you can't write to hard-sectored disks with a modern computer, not even one with a 5.25-inch drive. You'll have to find someone with a Northstar Horizon, to make you a "boot disk". The Horizons ran either NorthStar DOS, or CP/M. Contact me c/o my retrotechnology.com Web site to get a CP/M N* boot disk from me, for a modest fee. (there's an alternative way to create a bootable disk but you won't likely need to do that.) There's many N* owners around, welcome to the club!

                    There's talk about "punching your own disks". Could someone who has actually SUCCEEDED in punching their own disks and producing USABLE disks, please contact me? All I've heard is negative reports. 10-sector hard sectored disks sometimes are sold on eBay, or ask around for them. I don't have many to offer right now.

                    Documentation for the N* is readily available on on-line archives. "northstar horizon manuals" in Google will find them. You may find my Web page of manuals too, that way. Check my list of docs on my site, for ones that may not be available on line (mine are off-line, no apologies). I find it awkward to have to explain that reading a manual is important, and why, in the 21st century. So I'll put it this way: I'll insist on it, if you contact me more than a few times.

                    I've found the N* Horizons to be fairly easy to get back into service. If your machine is working, on reset (the red toggle switch in the back), one of the two floppy drives should start rotating and light up, for many seconds, then stop if there's no diskette. Clean the heads on your floppy drives and if you can, remove the drives and verify the drives on another machine. It would be sad if your drives had dirty heads, and the crap on the head scraped off the magnetic coating on your only boot diskette. Yes, that happens.

                    There's all sorts of things one can do to restore one of these systems. I discuss things I and others have done, on my Web site's "restoration" pages at:

                    http://www.retrotechnology.com/restore/r_restore.html

                    My Northstar manuals list and some N* discussion is at

                    http://www.retrotechnology.com/herbs_stuff/d_nstar.htm

                    Floppy disk hard sector stuff (and other details) is at

                    http://www.retrotechnology.com/herbs_stuff/drive.html#facts

                    I'll let my Web pages do the talking from here.

                    Herb


                    --- In midatlanticretro@yahoogroups.com, Kyle Owen <kylevowen@...> wrote:
                    >
                    > I got a chance to look at the N* again today. It looks like the disk
                    > controller is an MDS-AD3, from N*. Also installed is a CompuKit Econoram
                    > VII A board, with one of the 5 of the 6 rows of RAM fully populated.
                    > There's also a N* 16k RAM board, and the processor card, a ZPB-A2. The
                    > floppy drives are made by Tandon, and are both TM101-4s.
                    >
                    > I can't find too much info the particular floppy controller, other than
                    > that it appears to be a double-density unit. I suppose it's still using
                    > hard sectors.
                    >
                    > 73,
                    >
                    > Kyle
                    >
                  • wb4jfi
                    Herb: I will contact you separately as well, but I can report that I have very successfully punched both 5-1/4 N* and regular 8-inch CP/M floppy disks and used
                    Message 9 of 21 , Jun 9, 2012
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                      Herb:

                      I will contact you separately as well, but I can report that I have very successfully punched both 5-1/4 N* and regular 8-inch CP/M floppy disks and used both sides (single density). There were brands that this was a good practice with, and brands that were bad. Memorex were bad, 3M and Verbatim were OK, for example.

                      One issue was that you needed to make sure that the felt pad opposite the head was clean and in good shape. Otherwise, you ended up with scratches which did not affect the "main" side, but could cause severe problems when flipped to the head.

                      I made a small spatula-like thing from a business card, by cutting one long-edge into a rounded end. Next, I flipped a regular floppy upside down (after finding the index hole), and marking the place to punch on the target envelope with a Sharpie. Do this on both sides of the target floppy. Then, carefully put the rounded end of the business card betweem the envelope and the media (through the large center hole), to make a space between them. Punch the new hole where marked using a small, single-hole paper punch, while making sure the business card is between the metal punch and the media itself. The business card prevents the metal punch from scratching the media. I used to boxes at a time while watching TV. Now, I would have done it while waiting for a Windows machine to boot (ha ha).

                      As of two years ago, many of my "punched" 8-inch single-density 241k CP/M disks were still readable, even after almost 30 years. I don't have a N* system, so I can't authentiate those disks anymore.

                      My biggest problem with my main CP/M system is the old Tarbell whack-the-media-during-power-up syndrome. I've destroyed more disks by forgetting to open the drive door before powering up the IMSAI. Then, upon power-up, I hear that sickening clank, and I know another CP/M boot floppy has bit the dust...
                      Terry, WB4JFI

                      --- In midatlanticretro@yahoogroups.com, "s100doctor" <hjohnson@...> wrote:
                      >
                      > For those who posted "Herb will chime in"...I don't follow this mail list daily. If you think someone should contact me, please refer them to my Web site so they can do that. I have a specific Web page on Northstar, for instance, that would be a good link to have offered Kyle.
                      >
                      > Kyle, about your "northstar" system. With S-100 computers, you won't know what you have until you survey the cards. Now that you've done so, I can see it's mostly "Northstar".
                      >
                      > Northstar made floppy controllers as their first product, then offered whole systems. The Northstar Horizon (S-100 system) was pretty popular so there's a lot of these around. Almost all Northstar stuff used "hard sectored" diskettes, as discussed, including yours. It's 10 sector holes plus an eleventh hole as the "index". Look up "hard sectored floppy" on the Web to learn what that's about. By the way, that "10" is what Bill Degnan was probably talking about, OK?
                      >
                      > Kyle, you can't write to hard-sectored disks with a modern computer, not even one with a 5.25-inch drive. You'll have to find someone with a Northstar Horizon, to make you a "boot disk". The Horizons ran either NorthStar DOS, or CP/M. Contact me c/o my retrotechnology.com Web site to get a CP/M N* boot disk from me, for a modest fee. (there's an alternative way to create a bootable disk but you won't likely need to do that.) There's many N* owners around, welcome to the club!
                      >
                      > There's talk about "punching your own disks". Could someone who has actually SUCCEEDED in punching their own disks and producing USABLE disks, please contact me? All I've heard is negative reports. 10-sector hard sectored disks sometimes are sold on eBay, or ask around for them. I don't have many to offer right now.
                      >
                      > Documentation for the N* is readily available on on-line archives. "northstar horizon manuals" in Google will find them. You may find my Web page of manuals too, that way. Check my list of docs on my site, for ones that may not be available on line (mine are off-line, no apologies). I find it awkward to have to explain that reading a manual is important, and why, in the 21st century. So I'll put it this way: I'll insist on it, if you contact me more than a few times.
                      >
                      > I've found the N* Horizons to be fairly easy to get back into service. If your machine is working, on reset (the red toggle switch in the back), one of the two floppy drives should start rotating and light up, for many seconds, then stop if there's no diskette. Clean the heads on your floppy drives and if you can, remove the drives and verify the drives on another machine. It would be sad if your drives had dirty heads, and the crap on the head scraped off the magnetic coating on your only boot diskette. Yes, that happens.
                      >
                      > There's all sorts of things one can do to restore one of these systems. I discuss things I and others have done, on my Web site's "restoration" pages at:
                      >
                      > http://www.retrotechnology.com/restore/r_restore.html
                      >
                      > My Northstar manuals list and some N* discussion is at
                      >
                      > http://www.retrotechnology.com/herbs_stuff/d_nstar.htm
                      >
                      > Floppy disk hard sector stuff (and other details) is at
                      >
                      > http://www.retrotechnology.com/herbs_stuff/drive.html#facts
                      >
                      > I'll let my Web pages do the talking from here.
                      >
                      > Herb
                      >
                      >
                      > --- In midatlanticretro@yahoogroups.com, Kyle Owen <kylevowen@> wrote:
                      > >
                      > > I got a chance to look at the N* again today. It looks like the disk
                      > > controller is an MDS-AD3, from N*. Also installed is a CompuKit Econoram
                      > > VII A board, with one of the 5 of the 6 rows of RAM fully populated.
                      > > There's also a N* 16k RAM board, and the processor card, a ZPB-A2. The
                      > > floppy drives are made by Tandon, and are both TM101-4s.
                      > >
                      > > I can't find too much info the particular floppy controller, other than
                      > > that it appears to be a double-density unit. I suppose it's still using
                      > > hard sectors.
                      > >
                      > > 73,
                      > >
                      > > Kyle
                      > >
                      >
                    • s100doctor
                      ... Kyle contacted me, and we discussed what he s talking about. Turns out, he s talking about flippy disk technology. In the old OLD days, floppy drives
                      Message 10 of 21 , Jun 13, 2012
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                        "wb4jfi" <wb4jfi@...> wrote:
                        >
                        >
                        > Herb:
                        >
                        > I will contact you separately as well, but I can report that I have very successfully punched both 5-1/4 N* and regular 8-inch CP/M floppy disks and used both sides (single density). There were brands that this was a good practice with, and brands that were bad. Memorex were bad, 3M and Verbatim were OK, for example.
                        >
                        > One issue was that you needed to make sure that the felt pad opposite the head was clean and in good shape. Otherwise, you ended up with scratches which did not affect the "main" side, but could cause severe problems when flipped to the head.
                        > Kyle


                        Kyle contacted me, and we discussed what he's talking about. Turns out, he's talking about "flippy disk" technology. In the old OLD days, floppy drives were single sided. But most diskettes and all double-sided disks, have magnetic coatings on BOTH sides of the "cookie". Punching a hole through the ENVELOPE on the "opposite side" where the index hole is punched, lets you "flip" the disk over and use either side on a single sided drive. On a double sided drive this is moot.

                        What is in discussion in this thread, is 10-sector HARD SECTORED diskettes. The holes are sector holes in the "cookie", not a access hole in the envelope. Very different. Now I have to add "flippy disks" to my online collection of floppy information; another "lost art" of 20th century computing.

                        Herb Johnson
                      • David Gesswein
                        ... I hadn t realized disks were sold prepunched for flipping until I found a 3M box of them. Back in the day I punched them (poorly) myself.
                        Message 11 of 21 , Jun 13, 2012
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                          On Wed, Jun 13, 2012 at 10:30:51PM -0000, s100doctor wrote:
                          > Punching a hole through the ENVELOPE on the "opposite side" where the
                          > index hole is punched, lets you "flip" the disk over and use either
                          > side on a single sided drive. On a double sided drive this is moot.
                          >
                          I hadn't realized disks were sold prepunched for flipping until I found a
                          3M box of them. Back in the day I punched them (poorly) myself.
                        • Evan Koblentz
                          ... 3M box of them. Back in the day I punched them (poorly) myself. The first computer product I ever bought with my own money, vs. my parents, was a disk
                          Message 12 of 21 , Jun 13, 2012
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                            >> I hadn't realized disks were sold prepunched for flipping until I found a
                            3M box of them. Back in the day I punched them (poorly) myself.

                            The first computer product I ever bought with my own money, vs. my parents, was a disk notcher.
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