12 Mar
2011
12 Mar
'11
10:25 a.m.
Friends don't let friends store their archives on
a media that requires physical contact
with a read/write head.
As a data point: All of bitsavers fits on 27 DVD-R's.
I'm told that Blu-Ray recordables store 25GB (single layer) or 50 GB (dual layer) but
I'm
not at the leading edge of media adoption. Only in the past year have I grudgingly
admitted that DVD-R might be halfway decent for everyday use, but I still don't trust
anything but Gold CD-R for longer term use.
The mainframe people use cartridge-loaded WORM media which is 60 GB per cart. I think
it's magneto-optical but who knows, maybe it's really closer to Blu-Ray type
technology. For
a while (back in the 600 Mbyte/cart era) I was a big fan of the 5.25" magneto
optical
carts but CD-R and DVD-R is so easy that I have a hard time going back.
12 Mar
12 Mar
10:45 a.m.
On Sat, Mar 12, 2011 at 13:25, Shoppa, Tim <tshoppa at wmata.com> wrote:
By curious coincidence, one of my labmates just asked me for some
original data from my Master's thesis, and luckily I have that data
backed up on CD-R - from 1999 (Maxell gold-coloured CD-R74, if that
makes a difference). Tar.gz files, and still reads fine 12 years
later on a modern machine (Mac mini) without special hardware or
software.
I didn't plan on those being long-term storage, just as a snapshot in
case my HD crashes taking all my work with it. Of course, I still
have some C64 floppies from the 86-90 timeframe that I can read - but
that requires either well-kept original hardware or specialized HW and
SW.
However, joining this with the discussion of recovering from flash, I
believe that while not ideal as long-term storage medium, data on CD-R
can probably be recovered by digital archeologists long after a
consumer grade cd-rom drive deems it unreadable, provided no grievous
harm has been done to it. It might take some effort and specialized
knowledge and tools, but it's probably easier than recovering from
magnetic media.
Joe.
--
Joachim Thiemann :: http://www.tsp.ece.mcgill.ca/~jthiem
Friends
don't let friends store their archives on a media that requires physical contact
with a read/write head.
As a data point: All of bitsavers fits on 27 DVD-R's.
[...] but I still don't trust
anything but Gold CD-R for longer term use. 
11 a.m.
Speaking of DVD and archives too large to fit on one media, does anyone
have a good solution for pointing at a large file system (such as
bitsavers top level directory) and specifying a size of the target media
and let it sort out the archiving problem? I would like not to use an
archiver, but rather have the individual files copied to the target such
that they are available individually as files, as well as an index
somewhere specifying which item of the backup the file landed on.
I know this it not directly an archiving problem, but would be a nice
utility to have. It would work with either the problem of targeting
dvd-r or copying a large archive to a set of SATA drives.
Jim
On 3/12/2011 10:25 AM, Shoppa, Tim wrote:
I'm told that Blu-Ray recordables store 25GB
(single layer) or 50 GB (dual layer) but I'm
not at the leading edge of media adoption. Only in the past year have I grudgingly
admitted that DVD-R might be halfway decent for everyday use, but I still don't
trust
anything but Gold CD-R for longer term use.
The mainframe people use cartridge-loaded WORM media which is 60 GB per cart. I think
it's magneto-optical but who knows, maybe it's really closer to Blu-Ray type
technology. For
a while (back in the 600 Mbyte/cart era) I was a big fan of the 5.25" magneto
optical
carts but CD-R and DVD-R is so easy that I have a hard time going back.
11:53 a.m.
I have used DDS DAT for years, currently trying out DLT and AIT2 drives
(nice to have a 50GB native tape). While I have 100's of burnt CDs that are
15 years old by now, I don't think DVDr will be as good. And I still mess
around with MO drives for my old gear, picked up a few more drives in the
last year incase mine fail.
----- Original Message -----
From: "Shoppa, Tim" <tshoppa at wmata.com>
To: <cctalk at classiccmp.org>
Sent: Saturday, March 12, 2011 1:25 PM
Subject: Re: Digital archiving tools
Friends don't let friends store their archives on
a media that requires
physical contact
with a read/write head.
As a data point: All of bitsavers fits on 27 DVD-R's.
I'm told that Blu-Ray recordables store 25GB (single layer) or 50 GB (dual
layer) but I'm
not at the leading edge of media adoption. Only in the past year have I
grudgingly
admitted that DVD-R might be halfway decent for everyday use, but I still
don't trust
anything but Gold CD-R for longer term use.
The mainframe people use cartridge-loaded WORM media which is 60 GB per
cart. I think
it's magneto-optical but who knows, maybe it's really closer to Blu-Ray type
technology. For
a while (back in the 600 Mbyte/cart era) I was a big fan of the 5.25"
magneto optical
carts but CD-R and DVD-R is so easy that I have a hard time going back.
12:11 p.m.
On 12 Mar 2011 at 14:53, Teo Zenios wrote:
I have used DDS DAT for years, currently trying out
DLT and AIT2
drives (nice to have a 50GB native tape). While I have 100's of burnt
CDs that are 15 years old by now, I don't think DVDr will be as good.
And I still mess around with MO drives for my old gear, picked up a
few more drives in the last year incase mine fail.
I'm not so sure about CD-Rs, myself. Over the years, I've taken
pains to buy Mitsui (MAM-A) Gold media for my backups. About a month
ago, I pulled a 5-year old CD out to answer a question that I had.
The thing would not read--citing "unrecoverable" errors. Mind you,
the CD-R had been recorded, slipped into a jewel case and left in a
temperature- and humidity-controlled environment for that time. The
failed read was perhaps third read for the CD in 5 years.
Fortunately, I still had the data on an old hard disk.
CD-R as archival medium? I don't think so. DVD-R? I'm even less
optimistic.
I've had better results with DLT and QIC (for QIC, close to 30
years).
--Chuck
P.S. Anyone remember the short-lived Kodak warranty on their floppy
media that offered to recover lost data at no cost should it be due
to a media failure? That didn't last long...
12:25 p.m.
----- Original Message -----
From: "Chuck Guzis" <cclist at sydex.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Saturday, March 12, 2011 3:11 PM
Subject: Re: Digital archiving tools
I've had better results with DLT and QIC (for QIC,
close to 30
years).
--Chuck
I recovered a bunch of old QIC 120MB tapes a few years back (100+ tapes) and
every one read back fine, some dated to the late 1980's. The drive I used to
read them was not the drive that wrote them (the tapes were not mine).
3:53 p.m.
On Sat, Mar 12, 2011 at 02:53:54PM -0500, Teo Zenios wrote:
I have used DDS DAT for years, currently trying out
DLT and AIT2
*eek*
DDS tapes are _not_ a reliable backup medium, quite the opposite, they
can be a perfectly valid excuse why some annoying data has be "lost".
In a previous job, we used DDS3 tapes for boot & install (Ignite-UX tapes).
We always kept three copies of each tape and despite rarely using them
(well, how often do you reinstall a Unix production or even staging
server?) and the low machine count (IIRC < 10 machines) I aquired a
stack of 10 or 15 dead (== read errors) tapes in 2 years in that job.
As a contrast, the SDLT library had some 20 or so tapes in it, with regular
use (it being _the_ backup storage system) and it rejected (due to read errors
IIRC < 5 tapes in that same time.
In fact, from what I've seen, DDS tapes should be considered suspect
after 10-20 cycles (load/unload/read/write) and considered junk after
30-40 cycles. Plus there is the charming habit of some HP DDS drives to
very slowly drift out of alignment. So you can read the current and last
few generations of backup tapes on that drive but should it ever die ...
drives (nice to have a 50GB native tape). While I have
100's of
burnt CDs that are 15 years old by now, I don't think DVDr will be
as good. And I still mess around with MO drives for my old gear,
picked up a few more drives in the last year incase mine fail.
My MO drive unfortunately died, so I'm on the (low priority) lookout
for a replacement. But these days, my backups go either onto DLT-III(XT)
(10/15 GB native) or LTO1 (100 GB native) backup tapes. Both are linear
recording (as opposed to the helical recording of DDS) tape systems and
both are specced to keep their data intact for 20+ years and 500+ cycles
given proper storage.
Another backup medium I use is DVD-RAM, which sounds reasonably promising
as a backup storage medium, plus you can put a filesystem on it and run
r/w operations, simplifying access.
Kind regards,
Alex.
--
"Opportunity is missed by most people because it is dressed in overalls and
looks like work." -- Thomas A. Edison
2:12 p.m.
The mainframe people use cartridge-loaded WORM media
which is 60 GB per cart.
The mainframe people also keep at least a couple of generations of
backup technology alive as insurance. The nine tracks are just about
gone from the mainframe shops now, and 3480s are now what is finally
falling off the back end of the curve.
--
Will
2:16 p.m.
For
a while (back in the 600 Mbyte/cart era) I was a big fan of the 5.25" magneto
optical
carts but CD-R and DVD-R is so easy that I have a hard time going back.
I thought those things were great as well, but the WORM/MO people
never really managed to get their standards nailed down - some disks
and some drives did not like each other *some* of the time.
-.
Will
2:23 p.m.
On 3/12/11 5:16 PM, William Donzelli wrote:
Years ago I used quite a few of the 1.3GB 5.25" MO disks, a few
hundred of them. They were extremely reliable. I think their capacity
topped out at a little over 5GB, 5.2 maybe. It's a shame they didn't
push that technology further.
-Dave
--
Dave McGuire
Port Charlotte, FL
For
a while (back in the 600 Mbyte/cart era) I was a big fan of the 5.25" magneto
optical
carts but CD-R and DVD-R is so easy that I have a hard time going back.
I thought those things were great as well, but the WORM/MO people
never really managed to get their standards nailed down - some disks
and some drives did not like each other *some* of the time. 
9:22 p.m.
Shoppa, Tim wrote:
Friends
don't let friends store their archives on a media that requires physical contact
with a read/write head.
As a data point: All of bitsavers fits on 27 DVD-R's.
I'm told that Blu-Ray recordables store 25GB
(single layer) or 50 GB (dual layer) but I'm
not at the leading edge of media adoption. Only in the past year have I grudgingly
admitted that DVD-R might be halfway decent for everyday use, but I still don't trust
anything but Gold CD-R for longer term use.
I started to use DVD-R media around 2003 for my monthly backup for a
Windows 98SE
system with GHOST making the image file of the C: drive. Each monthly
was about 950 MB
and 4 * monthly would fit on one DVD-R along with an ASCII text file
with MD5 values for
each image backup file. I just copied one of the 2003 backups to a
current Windows XP
system and checked each of the MD5 values against the known value from
the ASCII text
file. ALL MD5 values were the same. I must thank Tim Shoppa for the
use of MD5 values
to verify that a file is unchanged. Also for using bzip2 for
compression. For large files that
compress easily, I will save the MD5 value for both the compressed and
uncompressed
version, but archive only the compressed version on one DVD-R along with
the file which
holds the MD5 values (I also record the size of the file).
Have I just been lucky? I plan to make up a few DVD-R media with just
the December 31st
backup to preserve one backup from the end of each year. Three DVD-R
should hold all
of the years along with a few individual files.
Has anyone else found that DVD-R media are satisfactory for 5 years at a
time?
The mainframe people use cartridge-loaded WORM media
which is 60 GB per cart. I think
it's magneto-optical but who knows, maybe it's really closer to Blu-Ray type
technology. For
a while (back in the 600 Mbyte/cart era) I was a big fan of the 5.25" magneto
optical
carts but CD-R and DVD-R is so easy that I have a hard time going back.
About 15 years ago, I acquired over a hundred magneto optical media for
the Sony SMO S-501
along with a few drives. Since they are 295 MB on each side (590 MB per
media - only one side
available at a time - these are flippies), the DVD-R media at 4.7 GB are
about 8 times the capacity
and 1/4 the thickness. So the magneto-optical can't compete with the
convenience of a DVD-R.
Does anyone have much experience with Blu-Ray reliability. I really
need a larger capacity media
when I switch to Windows XP as the monthly backup will likely be around
8 GB. Blu-Ray would
also reduce the bitsaver media needed to just TWO. Incredible. Also,
what is the current time
to read and / or write a 25 GB Blu-Ray media?
Jerome Fine
10:01 p.m.
On 13 Mar 2011 at 0:22, Jerome H. Fine wrote:
About 15 years ago, I acquired over a hundred magneto
optical media
for the Sony SMO S-501 along with a few drives. Since they are 295 MB
on each side (590 MB per media - only one side available at a time -
these are flippies), the DVD-R media at 4.7 GB are about 8 times the
capacity and 1/4 the thickness. So the magneto-optical can't compete
with the convenience of a DVD-R.
Depends on the MO media that you're using. Pinnacle Micro Apex
media, ISTR, is 4.7GB--and that's from the 90s.
Unfortunately, PMC in it's original version is no longer with us.
--Chuck
13 Mar
13 Mar
9:01 a.m.
On 3/13/11 12:22 AM, Jerome H. Fine wrote:
About 15 years ago, I acquired over a hundred magneto
optical media for
the Sony SMO S-501
along with a few drives. Since they are 295 MB on each side (590 MB per
media - only one side
available at a time - these are flippies), the DVD-R media at 4.7 GB are
about 8 times the capacity
and 1/4 the thickness. So the magneto-optical can't compete with the
convenience of a DVD-R.
You are comparing current-technology CD-form-factor technology with
very early magneto-optical technology. M-O peaked at over 5GB.
-Dave
--
Dave McGuire
Port Charlotte, FL
9:03 a.m.
On 3/13/11 12:22 AM, Jerome H. Fine wrote:
Does anyone have much experience with Blu-Ray
reliability. I really need
a larger capacity media
when I switch to Windows XP as the monthly backup will likely be around
8 GB. Blu-Ray would
also reduce the bitsaver media needed to just TWO. Incredible. Also,
what is the current time
to read and / or write a 25 GB Blu-Ray media?
I don't have any experience with Blu-Ray, so I can't answer your
question, but wow...doing a FULL backup every time (WAY excessive), and
doing it only monthly (WAY insufficient)? I can't even imagine living
like that. You really need to investigate some incremental backup tools.
-Dave
--
Dave McGuire
Port Charlotte, FL
4815
days inactive
4816
days old
13 comments
9 participants
participants (9)
-
als＠thangorodrim.de -
cclist＠sydex.com -
jhfinedp3k＠compsys.to -
joachim.thiemann＠gmail.com -
jws＠jwsss.com -
mcguire＠neurotica.com -
teoz＠neo.rr.com -
tshoppa＠wmata.com -
wdonzelli＠gmail.com