Enter DVD-RAM, it’s not a MO (magnetic optical drive), it works by cooking the disc to flip the bits. But still it’s a read/write optical disc, that uses lasers, what isn’t to love?

Well sadly the answer is pretty much eveything.

I think I found the format from the video “DVD-RAM: The Disc that Behaved like a Flash Drive” from Technology Connections.

Curiosity got the best of me, I paused the video, and bought 2 used discs for a whopping 3.99, and a 4.99 drive. Sure, it’s all cheap but how bad could it be? The discs were used in some DVD video production, and formatted UDF. I used XP to format them as FAT32. First thing is format from the CLI so you can clearly see what is going on.

I did this after the fact, and yeah bad sectors. This is the hint of why everything I tried on this blasted disc at best ‘kinda worked’ but for the most part didn’t. It’s not a little damaged, its totally worthless.

Battle Tech is so small it’ll fit with a copy of Windows/386 on a 1.44mb floppy disc, and yet the DVD-RAM struggled with this level of data.

I was going to do some kind of SQL bench thing of how terrible it was, but I couldn’t even create a database.

Everything I tried was non-stop failure.

I then tried the other disc for the hell of it.

Format complete.
    4,471,152 KB total disk space.
    4,471,136 KB are available.

       16,384 bytes in each allocation unit.
      279,446 allocation units available on disk.

           32 bits in each FAT entry.

Volume Serial Number is 941A-7AA7

And yeah, it worked. All my “simple” tests just worked, and they completed in a fraction of the time the other disc struggled and failed with. Using MS-DOS level file sized stuff it seemed to work great with, however remembering the optical drive they do love to spin up and down, and if the disc is spun down, reading files can take SECONDS… So that kind of sucked.

Formatting the disc takes 30-45 minutes. It is not fast by any stretch of the imagination. During the format you can hear the drive constantly spinning up and down. Clearly you can see why hard disks rock, as they can keep the media spinning at the same rate. I’m not sure if it’s seeking around a lot or what is going on. I have to wonder if it was possible for any drives to maintain a constant speed? Would it have mattered?

I’ve seen outrageous claims on how long the media should last, far too long for it to be viable. When I hear about all the early SEGA CD drives all dying, turns out those lasers don’t last for centuries, there is no way this media is going to be viable at all.

I have to wonder if there really is any validity to this medium. I mean I have 2 discs that were recorded on in 2008, and in 15 years I have a 50% failure rate. Not good.

It’d be really terrible to recommend this stuff for pretty much of anything. The spinup/spindown basically kill any hope of using it for random access.

It’s no surprise that the ever increasing capacity of flash drives, and the economies of scale driving prices of flash down killed any hope for optical media.

The real question is will any 8/16MB flash sticks work in 2024 and beyond?

It’s all so depressing. If you have anything even remotely important on any optical disks, get them over to NVME or hell anything else.

clik! box

Ever since I got dynamips, the cisco router emulator to actually run code compiled by GCC, I wanted to do something more fun than a simple game of planetfall with a memory mapped file.  And to make a router more like a real computer, I’d want some kind of disk.  Now most cisco routers have PCMCIA slots, so remembering back in the day iomega sold the click! drive, a 40MB removable disk cartridge that has a PCMCIA interface!  Neat!

And even better, on eBay I managed to fine one.  And much to my surprise when it arrived it was NIB, from 1999!

Contents of the box

As you can see, there isn’t much inside that box, a CD-ROM of the manual, a brief leaflet, and of course the drive itself and a single 40MB clik! cartridge.  I have to say that it’s all pretty neat.

The clik! disk, compared to a two dollar coin

The disk itself is pretty small.  It does remind me of the older minicomputer disk packs with a removable sleeve to protect the media, but like a three and half inch floppy it is spring loaded to keep users away from it.

Inserting the clik! disk into the drive.

The disk gently slides into the drive, to give a very satisfying ‘click’ sound to it.

Unfortunately for me, since this was one of those late night impulse purchases I should have remembered that the cisco 1701 series of routers does NOT have a PCMCIA slot, and the NPE-G1 on my cisco 7200 VXR, instead has a compact flash adapter, not the full PCMCIA.

OOPS.

While I do have a RSP 4+ with the PCMCIA slots, I don’t have a chassis or power supply so I can’t do anything with it anyways.  Unless I find the pinouts, and make my own harness to power it up, which I guess is always possible.

So close, but it went nowhere.  But I thought it was interesting enough to take a look at such a tiny storage solution from the turn of the 21st century.

So here is the problem. I want to delete some files from an IMD disk image, and then copy some new ones in.  Easy right? .. maybe.

Ok first up the easiest tool I’ve found to manipulate CP/M disk images is cpmtools.  Even better their pre-compiled binary is for Win32, so I’ll run it with Wine on OS X.  which works fine. Â Although there is one slight problem, cpmtools doesn’t read the IMD disk format.  So you will have to download imd118.zip from a backup of the late author’s computer.

Now using IMD you need to convert the OS disk into a ‘raw’ or ‘binary’ file.  Naturally IMD is a MS-DOS program so firing up DOSBox, I ran:

Uncompressing, so easy!

IMDU CPM68K12.IMD CPM.RAW /B

And a few seconds later I had my raw file.  Now the next thing was to manipulate the image in cpmtools.  cpmtools has a database of disk drive types, and naturally there is no definition for the SAGE2.  However thanks to a friend of mine (hi Lorenzo!) I took a look at 22disk, and found their demo version did in-fact have a definition for the SAGE:

BEGIN SAG2 Sage IV – DSDD 96 tpi 5.25″
DENSITY MFM,LOW
CYLINDERS 80
SIDES 2
SECTORS 8,512
SIDE1 0 1,2,3,4,5,6,7,8
SIDE2 1 1,2,3,4,5,6,7,8
ORDER SIDES
BSH 4 BLM 15 EXM 0 DSM 315 DRM 63 AL0 080H AL1 0 OFS 2
END

Which is great, however it took a bit of experimenting to work out how to format this information for cpmtools.  I compared a bunch of known formats, and then managed to work this out:

diskdef sage2
seclen 512
tracks 160
sectrk 8
blocksize 2048
maxdir 128
skew 1
boottrk 2
os 2.2
end

And now I can look at the image file!

$ wine cpmls -f sage2 CPM68K12.RAW
0:
ar68.68k
armath.sub
as.sub
as68.68k
as68symb.dat
asgo.sub
brwnies.txt
copy.68k
core.sub
cpm.sys
ddt.68k
ddt68000.68k
dump.68k
e.sub
find.68k
halt.68k
init.68k
linkcore.sub
lnk.sub
lo68.68k
m.sub
mcc.sub
mince.68k
mince.swp
mind.sub
orbit.sub
p.sub
pe.sub
pip.68k
print.68k
red.sub
redasm.sub
sage4utl.68k
sagebios.sys
screen.68k
setenv.68k
setprntr.68k
sig.txt
space.sub
spacem.sub
startup.sub
stat.68k
tlnk.sub

So, I tidy up the image and copy it back to the IMD program for compressing.  And this was, without a doubt the most difficult to figure out, until after a bunch of searching, and Lorenzo once more again pointed me in the direction of bin2imd

not intuitive!

So yeah.

BIN2IMD X.RAW X.IMD DM=2 N=80 SS=512 SM=1-8 /2

And the best part is that it worked!  So now I was able to transfer over a binary version of com.68k, com2.68k, along with Zork, and fire it up!

8080 Zork on 68k CP/M

Unfortunately, the interpreter doesn’t work right.  It could be the disk transfers fault, maybe the SIMH SAGE emulator, or even the 8080 emulator.  But it worked this far.