From: usenet@tim-mann.org
The entry for Model I VTOS double density is wrong -- it should be DTZ0,
not DPX0. VTOS 3.0 supported only single density (and had some funny
copy protection that I doubt MultiDOS worked with.) VTOS 4.0 supported
double density, but only if you were using the Lobo LX-80 expansion
interface. The LX-80 could boot disks with a double density track 0.
VTOS couldn't use a Doubler kit installed in a Radio Shack expansion
interface to do double density, as doublers first came out after VTOS
was no longer being supported.
Also, although Model I LDOS double density was originally always DTZ0
as listed (and thus double density system disks were bootable only on an
LX-80), later on the "SOLE" program was included. SOLE would reformat
track 0 of a double density system disk into single density to make it
bootable with an RS EI plus Doubler; i.e., DTX0. Data disks were still
all double density (DTZ0).
On 1 Jun 2006 23:22:10 -0700, "vad" wrote:
> Stumbled across Vernon Hester's analysis of the major TRS-80 DOSes.
> This excerpt comes from the MultiDOS manual, Cosmopolitan Electronics
> Corporation, 1984, and shows a good summary of different formats
> TRS-80 disks employed.
>
> Hopefully this might be used as a starting point for use in creating
> utilities made to analyze disk images. Perhaps someday we might have
> full fledged utilities for exporting and importing into these disk
> formats. (Open source code might be ported to various emulators and
> survive into a next gen platform.)
>
> Phil Ereaut has an interesting start with his "Emulator File and Sector
> Display" v9.0 utility. I hope he continues to improve it.
>
> If each of these four factors described below are looked at on a .DSK
> disk then for each duplicate in the "TYPE" category, additional
> hueristics might be added, e.g.
> * if the disk can be determined to be a type "DTX0" - that is
> "D" = Double Density
> "T" = True Logical Tracks (how is this tested?)
> "X" = track 0 and track 1 are different densities
> "0" = lowest sector is numbered zero.
> then the disk is a Model 1 Double Density disk, either DOSPLUS or
> MULTIDOS "D".
>
> An additional check might be made to look at differences between
> DOSPLUS and MULTIDOS"D" disks. Perhaps there is a sector on the
> MULTIDOS disk whose last 8 bytes are always "MULTIDOS". Are there
> clear differences between these two types of disks?
>
> Would tagging these disks properly be a good start for creating a good
> export/import program?
>
> To view correctly copy and paste into notepad or other text editor
> using COURIER FONT.
> ---
> From Vernon Hester, page 1 of the MULTIDOS manual:
> ==================
>
> MULTIDOS is a TRS-80 disk operating system developed to provide a means
> of
> communicating with other disk operating systems currently on the
> market. In addition, MULTIDOS contains major enhancements which make
> the
> program easy to use.
>
> The word "TYPE" in the chart below classifies all known operating
> systems
> and is determined by four factors.
>
> 1) The type of address marks used to identify the directory. "U"
> indicates
> USER DEFINED. "D" Indicates DELETED.
> 2) The use of pseudo-logical tracks. "P" indicates pseudo-logical
> tracks.
> "T" indicates true logical tracks.
> 3) Track zero formatted in a different density than the balance of
> the
> diskette. "Z" indicates the same density. "X" indicates a
> different
> density.
> 4) The lowest sector number assigned to each track. "0"=Numbered
> zero.
> "1"=Numbered one.
>
>
>
> MULTIDOS MODEL III/4
> MODEL I MAX/80
> MOD. SYSTEM DEN "TYPE" READ WRITE READ WRITE
>
> I TRSDOS S UTZ0 OK NOTE 1 NOTE 2 NOTE 2
> I NEWDOS S UTZ0 OK NOTE 1 NOTE 2 NOTE 2
> I VTOS S UTZ0 OK NOTE 1 NOTE 2 NOTE 2
> I ULTRADOS S UTZ0 OK NOTE 1 NOTE 2 NOTE 2
> I NEWDOS80-1 S UTZ0 OK NOTE 1 NOTE 2 NOTE 2
> I DOSPLUS S UTZ0 OK OK NOTE 2 NOTE 2
> I NEWDOS80-2 S UTZ0 OK OK NOTE 2 NOTE 2
> I LDOS S DTZ0 OK OK OK OK
> I MULTIDOS"S" S DTZ0 OK OK OK OK
> I DBLDOS D DPX0 OK OK OK OK
> I VTOS D DPX0 OK OK OK OK
> I NEWDOS80-1 D DPX0 OK OK OK OK
> I NEWDOS80-2 D DPX0 OK OK OK OK
> I MULTIDOS"P" D DPX0 OK OK OK OK
> I DOSPLUS D DTX0 OK OK OK OK
> I MULTIDOS"D" D DTX0 OK OK OK OK
> I LDOS D DTZ0 OK OK OK OK
> I TRSDOS D DTX1 NO NO NO NO
> III TRSDOS D DTZ1 VFU NO VFU NO
> III DOSPLUS D DTZ0 OK OK OK OK
> III LDOS D DTZ0 OK OK OK OK
> III NEWDOS80-2 D DPZ0 OK OK OK OK
> 4 TRSDOS D DTZ0 OK OK OK OK
> 4 DOSPLUS D DTZ0 OK OK OK OK
> 4 MULTIDOS D DTZ0 OK OK OK OK
> MAX-80 LDOS D DTZ0 OK OK OK OK
> MAX-80 MULTIDOS D DTZ0 OK OK OK OK
>
> VFU = VFU/CMD can copy a file FROM these types.
> NOTE 1: These types will have their address marks changed.
> NOTE 2 = Requires CONVERT/CMD to alter the directory address marks.
>
--
Tim Mann usenet@tim-mann.org http://tim-mann.org/
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