From: hoptoad!gnu@ucbvax.Berkeley.EDU (John Gilmore)
Newsgroups: rec.audio.high-end
Subject: Sony's Mini-Disc -- personal review
Date: 17 Dec 92 12:29:37 GMT
Organization: Cygnus Support, Palo Alto
NNTP-Posting-Host: 129.89.7.4
Originator: tjk@csd4.csd.uwm.edu


I have an Aiwa Mini Disc Recorder model AMD-100.  It is identical to
the Sony portable recorder, except that the top cover is silver rather
than black.  The salesman told me they are produced in the same
factory.  I bought this in the Akihabara in Japan two weeks ago; it was
the only unit I could find for sale.  All the other stores were glad to
take an order, but had none in stock; this store had exactly one unit.
Even the Sony store in the Ginza didn't have units for sale.

I am pleased with the audio quality and the form factor of the unit and
the media, but the firmware needs some serious QA, and they need to get
rid of the cruddy SCMS system.  Until the bugs are gone, I don't recommend
buying one.  I'm regretting that my warrantee is only good in Japan...

The drive cost Y79,000 or about $650.  Media cost Y1400/each for a 60-minute
recordable disc (about $11).  I bought two pre-recorded discs, Simon &
Garfunkel's Greatest Hits, and the Rolling Stones Flashpoint; these were 
Y2300 or about $19/ea.  The unit came with analog cables; digital cables
were supposed to cost an extra Y3000, but they threw them in for free.
The doc is in Japanese, with a short English translation at the back,
and the AC adapter is for 100V.  The local Fry's Electronics claims that
they'll have US drives within a week or two; so does Cambridge
Sound Works.

    - Frequency range? ( same as CD? Same as DCC )
The lit claims 20HZ -> 20KHz.  It sounds like a CD to me, but I'm no
audiophile.

    - Read only, read/write, write once?
Two kinds of discs are available -- read only and read/write.
R/O are stamped in a CD-like process.  R/W are magneto-optical.
Needless to say, the R/O ones they stamp out like cookies cost twice
as much.

    - Disk record/play time?
The read/write disks are 60 minutes.  The literature claims that in
Spring '93 they will offer 74-minute read/write discs.  The read/only
Stones disc is 76 minutes 51 seconds.  Given that they are using data
compression, they probably can't predict *exactly* how much a disc can
hold; it depends on the music.

I have successfully recorded both analog and digital, and transferred
the analog recordings to a DAT digitally.  I was unable to transfer a
digital recording to a DAT because of the SCMS (Serial Copy
"Management" System, i.e. copies of copies of copyrighted material are
rejected by the firmware).  I have not yet verified whether this
recorder has the vile attribute of some DAT SCMS decks, which assumes
that any analog input "must be" copyrighted, therefore making it
impossible for you to make multiple digital copies of *anything*,
including your daughter's first words or your own garage band.  If I
find out it's set up this way, it's the last thing I will use the drive
for.

The best part of the drive is that recording on it is like creating a
file on a computer, rather than like recording a tape.  You just press
record, and it records on an unused spot on the disc.  You don't have
to "position the tape" to anywhere, or worry about what you might be
recording over.  You can mark track boundaries as you record, or edit
them in later; go back and erase tracks, or reorder them.  The disc has
an alphanumeric name, as does each track.  In digital recording, the
track boundaries come over the wire (CD->MD), but I don't know if the
track names make it across from MD->MD.

When recording and playing, if you place your ear very close to where
you insert the disc, you'll hear it seeking around.  Cute.  I don't
understand why it has to seek when playing a prerecorded disc -- had *I*
written the code to pre-record a disc, I'd have laid it out sequentially.
The slight noise of seeking may be why there is no microphone built-in;
you have to buy one separately.

The disc medium itself is well human-engineered.  It's small -- a
couple of them fit *easily* into a shirt pocket, unlike 3.5''
floppies.  The media is durable, well sealed, and there is reasonable label
space.  They couldn't seal up the rear center of the disc (where the
motor spins it), so it's not completely sealed against dust, but your
fingers won't hurt it.  Magnets or speakers won't erase it, though high
temperatures may erase the read/write ones.  They wrapped about 4x
the packaging needed, around the R/O discs (another layer of plastic
box, plus a little booklet), and the R/W discs also come with another
layer of thick plastic, plus more labels which you have no place to store.
The media appears durable enough that you don't need all these extra
layers of protection.

I have a copy of the Sony catalog of pre-recorded titles; it doesn't
have 1000 titles to release next month -- more like 100 or 200 total.
I don't see the point of buying prerecorded music in this format anyway;
why pay a premium over CD?  Use it as a digital *recorder*; that's its
strength.

Unfortunately, the drive firmware has serious of bugs.  I recorded cuts
from several CD's onto a disc, added labeling, rearranged as desired.
Suddenly, track #12 would not play; the drive would say "Accessing"
forever if you tried, and I had to power cycle the drive.  I realized
that further fiddling with the disc might be dangerous, but had no
alternative -- you can't make a backup copy with one drive, like you
can with a floppy.  Indeed, two minutes' more fiddling caused the disc
to be completely lost; inserting it now says "BLANK DISC".  All my
recordings on that disc are lost, apparently forever.

It's not clear how to get firmware upgrades, how to report bugs, or
even how to tell what firmware rev you have, since it's a "consumer
product", not a "computer".  (It'd be cool to get upgrades on MiniDiscs,
of course, but they probably didn't provide for Flash or RAM firmware
patches.)  There is probably a "Norton Utilities" equivalent in the
firmware for service techs, but they didn't document how ordinary
mortals get to it to try to recover their irreproducible recordings.
It's not *nearly* as safe as audio tape in that respect, and the SCMS
won't let you make useful backup copies either (the copies can't be
copied), so you're simply screwed when a bug hits.

I have also gotten "Emergency Stop" messages when recording, which
stopped the recording and shut off the drive without warning.

Besides these most egregious bugs, there are numerous small problems.
It takes the drive about 5 seconds from when you hit record, to when it
actually starts recording; it seems to be reading the TOC (table of
contents) and free-space info.  You can his PAUSE and RECORD, wait the
5 seconds, then hit PAUSE to control the timing, but it's annoying.
The drive often makes annoying little accesses like this, causing one
or two seconds of delay when you ask it for something -- and it doesn't
buffer up your keystrokes, so you have to press the button again.  If
you have been editing the table of contents (adding or deleting
tracks), it buffers the edits in memory until you hit STOP, which then
involves five seconds of delay and losing your context (position on the
disc).  The manual warns that you shouldn't bump the drive while it is
doing this five seconds of TOC recording, but they should just do error
recovery there instead.  And should write the TOC as soon as they have
the bandwidth to do the writes; why wait?

They didn't manage the music buffer properly during scan-forward or
scan-reverse, so that when you press the button, you get a second of
silence, then compressed music while you hold it down, then half a
second of silence when you release it.  Also, the "Accessing..." delays
make the skip functions nonlinear and unpredictable.  It makes it
painful to do small skips when looking for something.  It tells you
what minute and second are playing, but if you skip forward and back,
it seems to lose perfect track.  You can't charge the battery while
using the drive, and the charging system wants to drain the battery
before charging it, which takes twice as long.  It seems they want you
to run around with half-charged batteries, risking field failure,
rather than charging them up whenever plugged in so that you will
always have maximum battery time when you unplug.  The drive bobbles
what it's doing when you switch from AC power to batteries, and you
have to start over.

The digital I/O jacks are the *same* physical jacks as the analog I/O
jacks.  It senses which one is plugged in, and adapts.  Unfortunately,
this means the drive doesn't use the standard digital I/O cables -- so
it's not clear how you plug two drives together.  (The digital cables they
supply have wierd-plug on one end and standard-digital-plug on the other.)
They only offer "fiber optic" digital I/O, as opposed to twisted pair
or coax, so you are stuck with expensive cables that are too fragile
to put in a backpack.

There are no plans to make the media available to computers, that I've
been able to find.  Sony has a similar magneto/optical disk under
development for computers, with a larger physical form factor.  This
means there won't be cheap drives for doing digital sound editing on
your Amiga, nor will there be consumer-priced media for recording your
computer data on.  My impression is that Sony wants to keep it that
way, to keep prices high and to not "rock the boat" about digital
copying of audio.

In summary, it's a valiant try, with plenty of warts.  If they fix the
warts, both technical and political, it could be a big success.  If
they don't, well, I'm glad they have competition.  I've been looking
for a medium to move onto from cassettes, and they're still in the 
running...
-- 
John Gilmore                gnu@toad.com  --  gnu@cygnus.com  --  gnu@eff.org
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