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26065Re: [midatlanticretro] Re: Booting a NorthStar Horizon

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  • Kyle Owen
    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!



      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.

      (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/
      > > > >
      > > >
      > >
      > >
      > >

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