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Path: utzoo!mnetor!seismo!brl-adm!rutgers!dayton!ems!umnd-cs!news
From: news@umnd-cs.UUCP (news)
Newsgroups: comp.sys.tandy
Subject: Re: CompuServe is closing down Orchestra-90 SIG
Message-ID: <359@umnd-cs-gw.umnd-cs.UUCP>
Date: Mon, 12-Jan-87 21:47:28 EST
Article-I.D.: umnd-cs-.359
Posted: Mon Jan 12 21:47:28 1987
Date-Received: Tue, 13-Jan-87 07:24:42 EST
References: <8217@topaz.RUTGERS.EDU> <2156@jade.BERKELEY.EDU>
Reply-To: rhealey@umn-d-ub.UUCP (Rob Healey)
Organization: U. of Minnesota, Duluth - Computing Services
Lines: 39
Keywords: ORCH90, COMPUSERVE, MODEL I/III Disk Compatibility

In article <2156@jade.BERKELEY.EDU> bowdidge@iris.berkeley.edu.UUCP (Robert Bowdidge) writes:
>
>Also, a question for all the TRSDOS wizards. I recently
>found a copy of Microsoft's muMath mathematics program (for
>the Model I) and the patches (from the Dec. 82 80 Micro) to
>get it on a Model III.  Unfortunately, for some really
>strange reason, such as the way the disk controller
>formatted these disks makes it impossible to read them with
>convert, super utility, or practically anything else on a
>Model III.  Right now, I'm trying to find some old friends
>with I's with disks to get the programs on a disk that I can
>read, but until then, can anyone tell me what ezzactly
>causes the problem? I was told it was that the 1771 disk
>controller marks sectors with a different set of bytes,
>making the 1791 ignore it all, and as such is a hardware
>problem. 

	The problem is in what is called a Data Address Marker (DAM). The
   model 1 used a marker that is immpossible for the controller in the 3/4
   to read on a sector basis. The only way you could read the disk is to use
   the Read Track command in SU and then manually edit the markers to something
   that the model 3/4 can digest. I would say try to find a model 1 buddy with
   LDOS 5.1.4 for the model 1, it'll be much easier that way. Sorry I couldn't
   solve your problem for you but I hope you have a better idea about why it's
   not working. If you can find a copy the book "TRS-80 disk & other mysterys"
   might help you, the title is close and IJG published it. The book is VERY
   rare so you probably won't be able to find a copy. If you have any other
   questions let me know. As a side, how many people read this group? I've
   never seen much activity on it so I decided I'd start talking. I've had
   various Tandy Z-80 systems since 1980 and have quite a bit of experience
   with the machines. Does anyone out there have a 1/3/4 question they'd
   like to ask? I might be able to help. Let's see if we can get some
   action in this group, it's way too quiet. How 'bout some, legitimate,
   sources being posted? I have a model 3 terminal program that works
   with vi and unix, even news. Would anybody be interested in it? Well,
   enough of me for today,

			-Rob Healey
			University of Minnesota, Duluth