SuperPET and 1541s
Tom Lake
I ask because I'd like to get a SuperPET but only have .d64 disk images
of the software. 1541s are easy to find and cheap but IEEE drives are
rarer and more expensive (can they even read disks created from .d64
images?)
Also, if anyone here has a working SP (disk drives, manuals and original
disks a plus!) they'd be willing to sell, let me know!
TIA
Tom Lake
Golan Klinger
The SuperPET doesn't have an IEC interface so there's no way to physically
connect a 1541 to it. You'll need a 2031, 2031LP, 2040 or 4040 to deal with
d64 images.
--
Golan Klinger
Dark is the suede that mows like a harvest.
Dragos
Tom Lake
"Dragos" <mgla...@gmail.com> wrote in message
news:49b026e2-aefc-4a17...@l21g2000vba.googlegroups.com...
> Don't forget you can use an MSD drive also :)
Yup. I'm watching an eBay auction now.
Tom Lake
sjgray
The 2031 and 4040 IEEE drives are read/write compatible with 1541
disks (D64 images). The MSD drives have both IEC and IEEE interfaces.
Also, Jim Brain's uIEC will supposedly support IEEE in the future and
let you use D64 images on a memory card.
I am currently working on a project for the CBM-II machines. The CBM-
II machines are like the PET in that they only have IEEE. However,
someone had produced a new kernal for it that uses a special cable
attached to the cassette port which gives the machines an IEC
interface. I'm working on an expanded cartridge that uses this system.
Once I have that working I was planning on adapting the code for use
on the PET machines, however it will be in 6502 mode, not 6809 mode.
I'm not making any promises as I'm just staring work on the CBM-II
code.
If anyone is interested in this please drop me a line...
Steve
bud
Group: comp.sys.cbm Date: Sun, Jun 21, 2009, 4:36pm (CDT-2) From:
mgla...@gmail.com (Dragos)
script:
>Don't forget you can use an MSD drive also :)
And that 'weird' 1541 look-alike which number I can't remember. They
_are_ expensive, too.
salaam,
dowcom
To e-mail me, add the character zero to "dowcom". i.e.:
dowcom(zero)(at)webtv(dot)net.
The fact that 'conventional wisdom' is indeed 'conventional',
does not, in any way, imply that it is wise.
Dragos
1541
as for using a 4040 as read/write compatable, that is simply not the
case. Read compatable yes, but format a disk in a 1541 then writing
to it on a 4040 will leave you less than pleased
The MSD is your best bet as it can connect natively to both systems.
> script:
bud
Group: comp.sys.cbm Date: Mon, Jun 22, 2009, 1:46pm (CDT-2) From:
mgla...@gmail.com (Dragos)
script:
>are you referring to the SFD-1001? it is
>in no way compatable with a 1541
That must be the one. Now that you mention it, I remember that it uses
one of the IEEE 488 drive formats. Looks like a '41, doesn't act like
one.
'Runs like a Deere, smells like a John."
sjgray
> are you referring to the SFD-1001? it is in no way compatable with a
> 1541
>
> as for using a 4040 as read/write compatable, that is simply not the
> case. Read compatable yes, but format a disk in a 1541 then writing
> to it on a 4040 will leave you less than pleased
>
> The MSD is your best bet as it can connect natively to both systems.
I agree the MSD is the best solution if you can find and afford one.
I did a quick check, because I never heard of problems between the
4040 and 1541. I formatted a disk on a 1541-II and took it to my 2040
drive (with DOS2 roms, effectively turning it into a 4040) and it read
fine. I saved a PET program on the disk and read it back no problems
on the 1541-II. Can you give details of the problems you have had?
Remember, C64's and PETs have different load addresses for files, so
you can't nesessarily load your C64 files on the PET without some
extra work.
Steve
Tom Lake
>> The MSD is your best bet as it can connect natively to both systems.
>
> I agree the MSD is the best solution if you can find and afford one.
Lucky me! I just won an MSD-2 on eBay. Now all I need is a SuperPET
to which to connect it!
Tom Lake
Spiro Trikaliotis
sjgray wrote:
> On Jun 22, 4:46ï¿œpm, Dragos <mglad...@gmail.com> wrote:
>>
>> as for using a 4040 as read/write compatable, that is simply not the
>> case. ï¿œRead compatable yes, but format a disk in a 1541 then writing
>> to it on a 4040 will leave you less than pleased
[...]
> I did a quick check, because I never heard of problems between the
> 4040 and 1541.
It's a problem with early ROM 1541 drives and the 4040. It is because of
the gap between the sector header and the corresponding sector body
("intra-sector gap"). On the 4040, it is 8 "data" byte, but on the early
1541, it is 8 "raw" byte. That is, the 4040 writes 10 "raw" bytes in the
gap, while the 1541 writes only 8 byte.
That's a when writing with a 4040 on a disk that was formatted with the
1541: When the 4040 switches on for writing (after waiting 10 raw
bytes), it is already in the SYNC mark that the 1541 had written. While
switching, the drive can write arbitrary values. If the value written
looks like a 0, the SYNC mark stops on reading: That is, the block will
not be readable, as the drive expects the sector marker ($08 as data
byte) after a SYNC (the remaining part of the 1541 sync), not another
SYNC (now, the right one).
Commodore found out about this and changed the 1541 behaviour in the
901229-03 ROM: Here, the intra-sector gap was made 9 byte long. This
way, it is much more unlikely that the 4040 will write after the sync of
the 1541 has been started, as there is only 1 byte difference. A SYNC,
however, must be 10 bit long (that is, 1 1/4 byte) in order to be
recognised. Thus, it is unlikely that the problem will occur. It could
only happen if the drives' RPM values are differing very much. I did not
calculate it exactly, but I think the difference would have to be that
much that it is unlikely the drives will be eable to read each other's
data in the first place!
Commodore most likely did not advance this gap to 10 byte in the 1541
(like in the 4040, which would reduce the risk to zero), as this would
mean disks written by early 1541 and later ones would not be compatible,
either.
Why did this problem happen in the first place? Well, on the 4040, the
CPU gives data byte to the hardware, which translates this to GCR. Thus,
the 4040 writes 8 data bytes, which are expanded to 10 raw bytes by
hardware. Obviously, the CBM engineers did not think about it and the
2031 (which is somehow a predecessor of the 1540, and thus, of the 1541)
wrote then 8 byte. Unfortunately, on the 2031, the translation to and
from is done by software. Thus, the 2031 writes 8 raw bytes.
This remained through all known (at least, to me) 2031 and 1540 ROMs.
The 1541 ROMS 901229-01 and 901229-02 still contain an 8, while the
901229-03 contains a 9 for the intra-sector gap. ($F58D and $FCD0 on
1540/1541 ROMs). All later 1541 drives (1541-II, 1541C) and the 157x
drives also already contain an intra-sector gap of 9 byte. I do not know
about the 1551, but I expect it to have a gap of 9 byte, too.
Regards,
Spiro.
--
Spiro R. Trikaliotis http://opencbm.sf.net/
http://www.trikaliotis.net/ http://www.viceteam.org/
VK4AKP
Just came across you posts while Googling for IEEE-488 info.
Love seeing people still dabbling in the old CBM gear!.
I started at CBM when the 64 came out. So my earliest computer was a
Vic-20, I missed all the fun of the early Pets unfortunately.
I have a couple of MSD-SD2 drives here that I am working on getting
going again.
One is 240VAC the other is 110VAC from USA.
Anyone know an easy source for the transformer so I can convert the
110VAC one to 240VAC internally?
Also I still have a 2031 in my collection here. And a BusCardII
interface from when I used to run a PunterNet BBS back in the good old
days. I had a set of 8250LP dual drives also but unfortunatly they are
long gone as CBM never returned them from service when they went
down. :(
Would love to get a SFD-1001 and a 2031LP for my collection if anyone
ever see's any going cheap?
~Ken - vk4akp. Sj of the RCC. http://shazam.zapto.org
.-.-.
On Jun 28, 6:28 am, Spiro Trikaliotis
<usenet-200...@spiro.trikaliotis.net> wrote:
> Hello,
>
>
>
> sjgray wrote:
> > On Jun 22, 4:46 pm, Dragos <mglad...@gmail.com> wrote:
>
> >> as for using a 4040 as read/write compatable, that is simply not the
> >> case. Read compatable yes, but format a disk in a 1541 then writing
Øyvind
back, but no plans to get rid of them just yet.
I do, however, have some parts for a 4040 that I don't need, if
anyone's interested (spare drive mechanism and some pcb's).
--
Øyvind