[Coco] Disk Basic and 512 byte block floppies.

[John Collyer]

It has a companion article to allow MS-DOS to read/write the other.  With
both of these articles
from the Rainbow it should give you insight into a way
of making a nice transfer program for the coco.

John Collyer

----- Original Message ----- 
From: "John Collyer" <johncollyer at zoominternet.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Saturday, January 17, 2004 8:17 AM
Subject: Re: [Coco] Disk Basic and 512 byte block floppies.


> See the July 1986 Rainbow article by
> Marty Goodman, "CoCo to MS-DOS"
> it reads/writes 512 byte sectors on a
> MS-DOS formatted floppies.
>
> John Collyer
>
> ----- Original Message ----- 
> From: "John E. Malmberg" <wb8tyw at qsl.net>
> To: <coco at maltedmedia.com>
> Sent: Friday, January 16, 2004 9:36 PM
> Subject: [Coco] Disk Basic and 512 byte block floppies.
>
>
> > After reading about how the IDE was supported on HGB dos, I decided to
> > try an experiment with ROM BASIC on a COCO II.
> >
> > I formatted a 720K 3.5 inch floppy with 512 byte sectors on OpenVMS
> > because ODS-2 puts some readable ASCII in the first sector.
> >
> >
> > I then put the floppy in the Color Computer, and used the DSKI$ command
> > to read the first sector.  The CLEAR 520 command is needed to reserve
> > enough string space.
> >
> > The text string "OPENVMS      is not a system disk" was clearly
> > displayed on the Color Computer.
> >
> > I then did A$="HELLO FROM COLOR COMPUTER", and used the DSKO$ command to
> > write it to the disk.
> >
> > Placing the Floppy back in the OpenVMS system and examing the first
> > block resulted in me seeing the same text.
> >
> > So it appears that it should not be too hard to patch DISK basic to deal
> > with 720K 512 byte blocked media.  Either simply using them at 1/2
> > capacity, or remaping the sectors beyond 9 to the other side or to
> > tracks beyond 35.
> >
> > Clearly more experiments are in order, but if a standard method of
> > remaping the sectors were developed, it would allow emulators on most
> > platforms to directly interchange floppies with the Color computer.
> >
> > At the minimum, it appears that I can use a BASIC program to write on
> > floppies that are readable on OpenVMS in a RAW form.  Which means it
> > will easily work on LINUX/UNIX also.
> >
> > There is documentation on the wild wild web for Microsoft Windows to
> > directly read and write to 512 byte media also.
> >
> > -John
> > wb8tyw at qsl.network
> > Personal Opinion Only
> >
> >
> > EAGLE> init/dens=dd dva0:
> > _Label: OpenVMS
> >
> > EAGLE> MOUNT/FOR DVA0:
> > %MOUNT-I-MOUNTED, OPENVMS mounted on _EAGLE$DVA0:
> >
> > EAGLE> DUMP DVA0:/BLOCK=(START:0,COUNT:1)
> >
> > Dump of device DVA0: on 16-JAN-2004 17:01:46.09
> >
> > Logical block number 0 (00000000), 512 (0200) bytes
> >
> >   03039401 001E65C0 11C00200 15C600A0 ..Æ...À.Àe...... 000000
> >   8BDFFF76 905F0000 000501FB 000609F7 ÷...û....._.v.ß. 000010
> >   20202053 4D564E45 504F0087 80FDFF74 t.ý...OPENVMS    000020
> >   73206120 746F6E20 73692020 20202020       is not a s 000030
> >   0000000A 0A0D6B73 6964206D 65747379 ystem disk...... 000040
> > EAGLE> DISM DVA0:
> >
> > Disk removed and placed in Color Computer and then returned.
> >
> >
> > EAGLE> MOUNT/FOR DVA0:
> > %MOUNT-I-MOUNTED, OPENVMS mounted on _EAGLE$DVA0:
> >
> > EAGLE> DUMP DVA0:/BLOCK=(START:0,COUNT:1)
> > Dump of device DVA0: on 16-JAN-2004 17:15:20.50
> >
> > Logical block number 0 (00000000), 512 (0200) bytes
> >
> >   524F4C4F 43204D4F 5246204F 4C4C4548 HELLO FROM COLOR 000000
> >   00000000 00000052 45545550 4D4F4320  COMPUTER....... 000010
> >   00000000 00000000 00000000 00000000 ................ 000020
> >
> >
> >
> > -- 
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> >
>
>
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