Benefits of a 1571 on the C64?

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Jim Faulkner

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Mar 4, 2003, 5:29:04 PM3/4/03
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I have both a 1541 drive and a 1571 drive. I'm planning on hooking
one up to my PC for transferring files and disk images, and hooking
one up to my Commodore 64.

According to the manual, the only benefit of using the 1571 is to
type in
OPEN 1,8,15,"U0>M1"
which allows you to use it in double-sided mode. I mostly just use
my C64 for playing old games and running demos, so I tried a couple
of double-sided games. Whether or not I typed in the above command,
however, the games still asked me to flip the disk.

Do any demos, games, or other cool things take advantage of a 1571
drive when connected to a Commodore 64? I'd rather have the better
of the two drives hooked up to the C64 since I'll be using it more,
but if there's no advantage then I'll just put it on my PC.

thanks,
Jim

Marc Nause

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Mar 4, 2003, 5:46:38 PM3/4/03
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According to a German book I read (Commodore 1571 & 1570 Das grosse
Floppybuch by Rainer Ellinger), you can use the fast busmode of the 1571 by
connecting SRQ and DATA of the CIA1 with pin 4 and pin 5 of the USER-Port.

You also need some code to change the Kernal, which turns off the tape
routines of the C64, but gives you fast access to the 1571.

The routine is not very long, I can scan it from the book if anybody really
wants it.

Greetings

Marc

--
http://low.audioattack.de | http://www.audioattack.de

mike

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Mar 4, 2003, 8:49:54 PM3/4/03
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In article <C411882C36E67123.400937D4...@lp.airnews.net>,
"Jim Faulkner" <jfau...@ccs.neu.edu> writes:

>ccording to the manual, the only benefit of using the 1571 is to
>type in
>OPEN 1,8,15,"U0>M1"
>which allows you to use it in double-sided mode. I mostly just use
>my C64 for playing old games and running demos, so I tried a couple
>of double-sided games. Whether or not I typed in the above command,
>however, the games still asked me to flip the disk.
>

You have mis-understood the meaning of double-sided mode (1571 mode). In this
mode the drive treats both sides of the disk as if they are one continous side.
This gives you twice as much room, 1328 blocks free instead of only 664
blocks. Of course the disk must be formatted in the 1571 mode. Note that the
1571 boots up in 1541 mode on a 64. You must issue the u0>m1 command to put it
in 1571 mode.
If you had a 128 it would boot up in the 1571 mode when in 128 mode.

Mike
University Place Commodore User Group (UPCHUG)
Tacoma, WA USA


White Flame (aka David Holz)

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Mar 5, 2003, 6:43:55 AM3/5/03
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"Jim Faulkner" <jfau...@ccs.neu.edu> wrote in message
news:C411882C36E67123.400937D4...@lp.airnews.net...

> Do any demos, games, or other cool things take advantage of a 1571
> drive when connected to a Commodore 64? I'd rather have the better
> of the two drives hooked up to the C64 since I'll be using it more,
> but if there's no advantage then I'll just put it on my PC.

Most (>99%) games and demos are written for the 1541. For any program that
loads or saves data using standard compatible methods like application
software or editors, you can use the full double-sided capacity as data
storage. You can also load up single-file demos and games onto a
1571-formatted disk.

--
White Flame (aka David Holz)
http://www.white-flame.com/
(spamblock in effect)


Wolfgang Moser

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Mar 5, 2003, 11:11:00 AM3/5/03
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Hello Marc,

Marc Nause wrote:
> According to a German book I read (Commodore 1571 & 1570 Das grosse
> Floppybuch by Rainer Ellinger), you can use the fast busmode of the 1571 by
> connecting SRQ and DATA of the CIA1 with pin 4 and pin 5 of the USER-Port.
>
> You also need some code to change the Kernal, which turns off the tape
> routines of the C64, but gives you fast access to the 1571.

Interesting, I always knew, that this is possible with
a few lines of code, like with Pasis Burstloader at:
http://www.cs.tut.fi/~albert/Dev/burst/

But I never heard of such a kernal replacement, which
would give one instant fast access to burst mode
equipped drives like the 1571 or 1581.


> The routine is not very long, I can scan it from the book if anybody really
> wants it.

Yes please, you could place it onto a webpage or send
it to me via mail. Maybe I can manage to get it OCR'ed
or perhaps create a ready built Kernal replacement of
it.

It's not only this possible speed improvement, I like
of the 1571, but also that it's very compatible to the
1541 drive in one way. It comes with a working
track-0 light barrier support and MFM encoded disks
can be read/written.
And the best of it is a index hole detector, which can
probably be used for better nibble programs to copy
protected disks (or to transfer them into G64 images).


Womo

Zed Yago

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Mar 5, 2003, 11:55:52 AM3/5/03
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Marc Nause <Low...@gmx.de> wrote in message news:<b43acg$1gedr7$1...@ID-147064.news.dfncis.de>...

> According to a German book I read (Commodore 1571 & 1570 Das grosse
> Floppybuch by Rainer Ellinger), you can use the fast busmode of the 1571 by
> connecting SRQ and DATA of the CIA1 with pin 4 and pin 5 of the USER-Port.
>
> You also need some code to change the Kernal, which turns off the tape
> routines of the C64, but gives you fast access to the 1571.
>
> The routine is not very long, I can scan it from the book if anybody really
> wants it.

Pasi Ojala has made something similar, look at:
http://www.cs.tut.fi/~albert/Dev/burst/

Have Fun,
Zed Yago

Marc Nause

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Mar 5, 2003, 12:45:08 PM3/5/03
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Wolfgang Moser wrote:

> Yes please, you could place it onto a webpage or send
> it to me via mail. Maybe I can manage to get it OCR'ed
> or perhaps create a ready built Kernal replacement of
> it.

I have scanned the chapter from the book. You probably know much better what
they discribe in it than me. I have uploaded the images to
http://www.tu-bs.de/~y0018680/1571/

Tell me if you need better quality.

Paul Rosenzweig

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Mar 5, 2003, 1:09:27 PM3/5/03
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Marc Nause <Low...@gmx.de> wrote in message news:<b43acg$1gedr7$1...@ID-147064.news.dfncis.de>...

> According to a German book I read (Commodore 1571 & 1570 Das grosse

> Floppybuch by Rainer Ellinger), you can use the fast busmode of the 1571 by
> connecting SRQ and DATA of the CIA1 with pin 4 and pin 5 of the USER-Port.
>
> You also need some code to change the Kernal, which turns off the
> tape routines of the C64, but gives you fast access to the 1571.
>
> The routine is not very long, I can scan it
> from the book if anybody really wants it.

Before I installed my RAMLink (with JIFFYDos), I used a program, from
RUN magazine by MICHAEL MILLER of BIG BLUE READER and SOGWAP fame,
to accelerate loads from 1571 and 1581 drives. The program may have
worked on stock C64's as well. For loads from drives other than 71's
and 81's, the program jumped to the default loader in the C64 ROM. I
don't have a clue about how the program accelerated loading. I had
to modify the program because it occasionally corrupted the 1571 BAM.

Wolfgang Moser

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Mar 5, 2003, 2:12:59 PM3/5/03
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Hi Marc,

Marc Nause wrote:
> I have scanned the chapter from the book.

Thanks, I already GIMPed them a little bit and put
them into a PDF. OCRing was not possible, because I
had to correct too many words (rewriting would be
faster).
http://d81.de/shared/Floppy1571-Burstmode.pdf

Womo

Wolfgang Moser

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Mar 6, 2003, 4:15:39 PM3/6/03
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Hello,

with the rescan I was able to convert this section into
ASCII text. Have a look at:

http://d81.de/shared/C64-Burstload-Kernal.txt

It may contain some errors/bugs, that I didn't find by
proof reading this text.


Womo

bud

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Mar 7, 2003, 4:11:05 AM3/7/03
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'Lo Wolfgang:

Group: comp.sys.cbm Date: Thu, Mar 6, 2003, 10:15pm (CST+7) From:
wn...@d81.de (Wolfgang Moser)

sccript:

Thanks WoMo. Sooner or later I'll run my copy thru a translator.

salaam,
dowcom

--
http://community.webtv.net/dowcom/DOWCOMSAMSTRADGUIDE

DOShead Credo:
a) Try it! It might work.
b) GOTO a).

Wolfgang Moser

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Mar 9, 2003, 12:06:46 PM3/9/03
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Hello Marc et. al.,

Marc Nause wrote:
> I have scanned the chapter from the book. You probably
> know much better what they discribe in it than me.

in the meantime I got managed to fully proof read the
eText converted doc by disassembling the typewrited
binary listing and comparing it to the ROM listing
shown.
I also created a readily prepared Kernal ROM replacement
(btw. you have to redo one single patch to make use of
an EPROM Kernal instead of the RAM driven one).

Today I made some tests with a C64 modified as described
and yes, it works. A 202 blocks file could be loaded
within 18 seconds instead of 2 minutes with a C1571 drive.

But there are some disadvantages: The routine shown in the
book does only improve _loading_, it's no general speeder
system. If you compare it with real Floppy Speeders
(SpeedDOS, JiffyDOS, Dolphin-DOS), this ROM is missing
many functions and a general improvement of all disk
based accesses. Another drawback is, that you have to
POKE different value into address 828 to enable or disable
the Burstloader, if you want to access different drives
like a C1571 as device 9 and a C1541 as dev8.

It's only a tiny example I think.


Another Burstmode replacement kernal appeared in the
german 64'er magazine, issue 09/1986. The hardware mod
presented there is incompatible to the one above, because
it utilises the fast serial line from CIA2 instead the one
from CIA1.
I also tested this Kernal, but didn't resolder the serial
lines and could see, how fast it works or which disk
operations are improved. The patches incorporated into the
"DTE FSD-System" are much bigger than the ones from
Ellinger so I assume, this Kernal got much more
functionally. I also assume, that it can autodetect, if the
fast serial mode can be used or not (differing between C1541
and C1571 drives).


In a personal talk Nicolas Welte mentioned some other
circumstances. He thinks, that the C1571 has to be switched
to 2MHz mode for using their burst mode routines. That would
also mean, that the drive is switched from the
"1541 compatibility mode" to the "native 1571 mode" with
decreased (or none) compatibility to C64 related
applications (copy protections).
This may decrease the advantages of such Burstmode routines.

Pasi Ojala mentioned, that with the C64 the datasette may
interfere with the fast serial lines (SRQ-In), you mustn't
have connected a datasette, if you want to load programs
with the Burstmode.


Perhaps a completely new class of speeder system has to be
developed, that:
1. utilizes fast serial transfers instead of incorporating
parallel cables
2. integrates the needed Burstmode hardware into the C1541
drive, so that it can also be speeded up
3. some better hardware modification to the C64, so that
the fast serial lines don't interfere with the datasette
4. probably some alternative hardware mods for the C128, so
that the Burstmode cannot only be used in the C128 mode
there, but with C64 mode, too
5. general Floppy Speeder improvements for the Commodore
disk drives (8kB RAM), so that the loading times become
even shorter. With the C1571 a burstmode routine should
also be integrated into the 1541 compatibility mode, so
that the drive doesn't neede to be switched into 2MHz
mode anymore
6. ensuring compatibility to CMD's drives, who also support
the Burstmode
... to be done, ... preferably, when normal live is over :-)


All the files mentioned here and in earlier posts have been
recollected on my new "R.I.P" (rest in _pieces_) web page,
the URL is:

http://d81.de/R.I.P/#C64BM

All the links mentioned in earlier posts are not valid anymore.


Womo

Rud...@xmas.com

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Mar 10, 2003, 10:08:09 AM3/10/03
to

Double sided games designed for the 1541 do not work on the 1571
because the disk would need to spin the opposite way when trying to
read the second side which is not possible.

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