Path: utzoo!attcan!uunet!cbmvax!fred
From: fred@cbmvax.UUCP (Fred Bowen)
Newsgroups: comp.sys.cbm
Subject: Re: Side "H1" of a #1571 Disk.
Message-ID: <5792@cbmvax.UUCP>
Date: 26 Jan 89 00:07:47 GMT
References: <317@hal.UUCP>
Reply-To: fred@cbmvax.UUCP (Fred Bowen)
Organization: Commodore Technology, West Chester, PA
Lines: 34

In article <317@hal.UUCP> hxh@hal.UUCP (Howard Hermann) writes:
> [...] To make the second side of [a single-sided] disk, with its 160k of
>space available for additional program material [...] using U0>M0, and U0>H1,
>and HEADER, I got a successful format of the top side [...]
>
>Several programs were then saved to side H1, quite easilly.  The prob I have
>run into, however, is that of loading these programs from side H1.  A program
>that loads in 4 seconds from a #1581, or a double-sided formatted #1571 disk,
>now takes over 32 seconds to load, from side H1, of this two-sided disk.

You must be in "1541" mode to select the top side of the disk ("H1"), therefor
all loads are performed in slow 1541 fashion.  If you attempt to select side
"H1" in "1571" mode, you will get a DOS error #31, syntax error.  (I believe
this is described backwards in the 1571 manual).

>I know the ROM corrected the prob with double-sided formatted disks,
>but wasn't it also supposed to correct the prob with a two-sided formatted
>disk?  Any suggestions for getting side H1 to load as fast as side H0 would
>really be welcome.

The ROM upgrade enables the drive to recognize the type of disk you just
created without a lengthly think-and-blink session (due to backwards data
but valid sync marks on the top side).  You get fast (burst) loads only when
the drive is in "1571" mode (don't confuse a disk with two separate sides
with a double-sided disk).  You could write your own routine to accomplish
what you want; I don't know of anyone who has done that.  Isn't it possible to
combine the files on the two diskettes into one normal double-sided diskette?
--
-- 
Fred Bowen			uucp:	{uunet|rutgers|pyramid}!cbmvax!fred
				arpa:	cbmvax!fred@uunet.uu.net
				tele:	215 431-9100

Commodore Electronics, Ltd.,  1200 Wilson Drive,  West Chester,  PA,  19380