The Sony Playstation and Sega Saturn Backup
FAQ (v1.1) 9/17/95
Backing up disks for the Playstation and Saturn is no easy task, since
it requires plenty of software and in most cases, and some expensive hardware
to boot. My hardware recommendations are
(1) A note on the format of Sony and Sega disks.
It is a good idea to have some background on Sony and Sega disk formats.
The Sony disk is basically a CD-ROM XA mode 2 disk with audio tracks. The
Sega disk is basically a CD-ROM mixed mode, mode 1 disk. However, both systems
implement a copy protection technique. The sony disk adds a special encoding
on a series of sectors near the beginning of the disk. This special encoding
renders it unreadable on most cdrom drives and the playstation detects for
its
presence on bootup. On the sega, there is a special track on the far outside
rim of the cdrom. This special track is probably uncopyable, because it
appears
to have large areas of absolutely blank sections, with no sync information
your
CD couldn't establish proper speed or even reach the correct location. The
track is also at the far outside rim, leaving unformatted data between the
data
track and special track. The special track on the Sega appears to be identical
on both US and Japanese roms. We note that Sony disks are more prone to
damage
than Sega disks since their mode 2 format can preclude ECC bytes which reduces
error correction rates. For those of you with japanese systems, it becomes
increasingly important to backup since your software is costing you ~$100
a
disk, it is worth spending a little bit more so that you don't damage your
disks by accident.
(2) Duplicated Disks
A duplicated disk will never be exactly identical to the original. I
doubt that anybody could actually copy the sega protection track, so we
won't
even try. I have some ideas about copying the sony track. If the sony psx
determines the illegal track by detecting an error, there are ways you can
format a disk to create an error. One example would be to write the entire
image using 2352 byte sectors, and purposefully screw up the 12 sync bytes,
the header, or using nonsense ECC bytes where the protection sectors are.
That
involves some special CDR software and determining the protection sectors
can
be a long process using a CD-Rom drive sensitive to the protected sectors.
Instead, we will use one of the swapping methods to start these copies.
(3) Duplication
I recommend that we do all the reading on a proper cdrom drive that
is capable of reading digital audio (DA) since many games have standard
CD-DA
tracks. Drives capable of doing this include
Reading the audio is best accomplished by using the CDDA utility included
in
Corel Scsi 2.0 and up. Notice that reading CD-DA is not a very trivial process.
Since DA is stored with no header data, you cannot guarantee that when you
seek to a certain sector, you will arrive on the proper spot. Many times,
you can end up arriving within 1 or 2 bits of the proper target. Some software
uses a trick called jitter reduction to improve accuracy using a two pass
technique, but it is very slow. The moral of this story is reading DA does
not guarantee you a bit to bit accurate copy of the DA track. The accuracy
varies from brand to brand. NEC drives seem to have a higher rate of errors,
as do all IDE drives. We highly recommend the use of SCSI drives for reading
DA regardless of your software. Also, some drives only support reading of
DA at single speed, even if its data speed is double or quad (Toshiba).
That
can greatly hinder your duplication. I personally have no experience with
the Sony drives, but I have heard that they work.
After this, we can read the data tracks. On the Sega, the data track is
mode 1
and unprotected so any drive can read it. On the Sony, however, the track
is mode-2 and it also has the protected sectors. Drives capable of reading
these protected sectors include
I haven't had that much luck finding drives that can read these sectors,
but
if you have a pioneer, you're set. The Teac isn't on the DA-capable list,
so
it's not a big help. However, if you already have a DA capable drive that
hangs while reading the data tracks, this drive is an inexpensive alternative.
To read the tracks, we need to make a note on orange book standards when
using
CDRs. At the end of each track, it is normal practive to add two sectors
of
leadout. This means that when you copy a track, make sure you read two fewer
sectors than the length of the track. This corresponds to 4096 bytes for
sega,
and 4672 bytes for sony. In addition, there is a 150 sector gap between
tracks.
Some software seems to think that this is part of the previous track, and
grab
that too. When using CDDA to read audio, simply shorten the length of the
read
by 2 frames. When using the program CD Grab Professional, please shorten
the
length by 152 sectors. When using CDCP, version 1.1, the length is correct.
When using CDCP Version 1.2 and later, shorten the length by 152. Some software
seems to give you control of wheter the data file includes the 2 orange
book
sectors, and will not create a oversize track. Note, on some software, the
track will be the minimum sector size. In that case, it will become necc.
to shorten that track by 2 sectors. Luckily, this would mean the track has
to be an audio track, and so the loss of 2/75 of a second is no big deal.
Caveats:
During production, some companies use some shortcuts to speed up
production. One good trick is to use direct sector access to audio tracks.
It allows quicker access to audio tracks, but requires that the exact sector
be
provided. Usually, the audio track appears immediately after the data track,
so the exact position of the audio track is unknown until after the data
track
is finalized in production. The shortcut is to place the audio tracks at
a
predetermined location, say, at the 100 megabyte point and require that
the
data track be 99 megs or less. In this case, when the data track is finished,
there maybe a unformatted region between the actual end of the data track
and
the audio track. However, reading the table of contents will reveal an
improper length for the data track that spans all the way to the audio track,
including the unformatted region. This will cause an error when you are
trying to read the data track; the cd will suddenly stop reading when it
reaches that point. The solution is to pad the data track file with empty
sectors. For example, a 2048 byte file of zeros will do for sega, and 2336
byte
file for sony. Pad the file until it is the same number of sectors as what
the
software reports as the length of the data track.
Software:
One report is that the highly regarded Corel CD Maker doesn't allow the
writing of disk images without a plugin. What a crock! Get EZ-CD pro instead,
it will be cheaper than Corel to get this working. EZ-CD is bundled with
Pinnacle and Ricoh CDRs, among others. Corel does allow you to directly
copy
audio tracks from a cdrom to a cd-r, while ez-cd allows you to directly
copy
mode 1 tracks from a cdrom to a cd-r. Note that direct copying means you
don't need a buffer file on the hard drive, and can save 50% off your copying
time.
(4) Playing PSX:
To play the game, you have to use one of the swap techniques. On the
PSX, you insert the original disk, and swap when you see the ps logo while
holding down the "drive closed" button. If you don't trust this,
go into
cd player. Insert original disk. press the drive close button, old, insert
copy, and go to exit (Still holding down the close button). Note, that
doing it this way, the ps reads the table of contents from the original
disk.
For games from Namco and Bandai, this information is used to determine the
length of audio tracks. Always use the original disk to start the copy for
these games if you want properly working audio. Of course, since you have
the original game, this would never be a problem, unless you are trying
to play
a japanese game on a US system. In that case, you're somewhat screwed. To
play a japanese game on a US system, the original disk has to be a US disk,
but the copy disk can be any country. In this situation, the track size
on
the original determines the length of the track on the playback, and if
you
use the US demo disk to start, say, ridge racer, the short audio tracks
on the
demo disk will cause problems. Get a copy of Tekken for your US PSX if you
want a generally good start disk to play japanese games.
(4) Playing SATURN:
On the Saturn, however, things are easier in some ways, harder in
others. To begin with, it requires a double swap technique. First, you
insert the copy. start the machine, and it reads in the TOC. When you hear
it seek to the special track (And slow down), swap to the original. When
it seeks back, pop back in the copy. Of course, to do this, you will have
to trigger it so that it thinks the drive door is always closed. To do this,
open up the saturn. There is a wire that runs from the drive door to a plug
on the left side of the CD mechanism. Unplug the plug, and short out the
two pins in the jack. You can do this by applying some solder to it, shoving
a
screw in there and taping it down, or some other creative trick. Because
it reads the TOC from the copy, you can insert any original disk (such as
the US saturn's sample disk) so you can keep your precious originals safe.
Additions to doki@waku.com
Corrections/suggestions to Doki@waku.com
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