23 Mar
2015
23 Mar
'15
11:46 a.m.
I've been recovering old data from computers that I used many years ago,
the last effort was trying to recover the data from a hard disk that ran
a WFW 3.11 system. The problem was the disk could not be read on a
modern computer, so I recreated an old system and (very lucky for me)
ftp'd the data off the system after I found an ISA network card.
I have a couple of 4mm and 8mm tapes that contain data I want to
recover. The 4mm is DDS-1 and was written using tar on a SGI system in
1998. My questions are;
'What modern DAT tape drive will read this tape? How backward
compatible is this technology?'
This seems like an easy problem and intend to use a linux system to read
the tape.
The 8mm tapes were also written on an SGI system, however it was in 1994
and the IRIX Backup utility was used. IRIX 5 was probably used. Any ideas?
23 Mar
23 Mar
12:12 p.m.
My experience is that if you can find an Exabyte EXB-8500, you can
probably read that 8mm, newer drives may also work just fine (it's been
enough years, I forget just how new of drives we've been able to read
8mm tapes of that vintage on.
What's likely to be difficult though is the 4mm tape. The 4mm DDS tapes
are probably proprietary to the drive model, and potentially to the
drive they were written in (if the heads were out of alignment). I hate
trying to recover 4mm data. Was it written using a SGI branded drive?
If so that would make things easier. Actually if it was written a drive
that was relatively new in 1998 it might be easier, buy then things were
fairly standardized.
No clue on the Linux/IRIX question, but I would imagine Google can help
you there, as that seems like a common enough problem.
Zane
On 2015-03-23 08:46, Douglas Taylor wrote:
I've been recovering old data from computers that
I used many years
ago, the last effort was trying to recover the data from a hard disk
that ran a WFW 3.11 system. The problem was the disk could not be
read on a modern computer, so I recreated an old system and (very
lucky for me) ftp'd the data off the system after I found an ISA
network card.
I have a couple of 4mm and 8mm tapes that contain data I want to
recover. The 4mm is DDS-1 and was written using tar on a SGI system
in 1998. My questions are;
'What modern DAT tape drive will read this tape? How backward
compatible is this technology?'
This seems like an easy problem and intend to use a linux system to
read the tape.
The 8mm tapes were also written on an SGI system, however it was in
1994 and the IRIX Backup utility was used. IRIX 5 was probably used.
Any ideas?
12:21 p.m.
----- Original Message -----
From: "Douglas Taylor" <dj.taylor4 at verizon.net>
To: <General at classiccmp.org>; "Discussion at classiccmp.org:On-Topic
Posts"
<cctech at classiccmp.org>
Sent: Monday, March 23, 2015 4:46 PM
Subject: Recovering data from 4mm and 8mm tapes
I have a couple of 4mm and 8mm tapes that contain data
I want to recover.
The 4mm is DDS-1 and was written using tar on a SGI system in 1998. My
questions are;
'What modern DAT tape drive will read this tape? How backward compatible
is this technology?'
The 8mm tapes were also written on an SGI system, however it was in 1994
and the IRIX Backup utility was used. IRIX 5 was probably used. Any
ideas?
DDS-1 can normally be read on DDS-2, in my experience. I seem to remember
that Sony and HP DDS drives of that generation are not totally
interchangeable, especially for the compression routines. But I might
confuse it with some other system.
Are the 8 mm tapes Exabyte format? Exabyte drives are normally 1 or 2
versions upwards compatible, so you can read 8200 tapes on 8500 drives, but
probably not on Eliant drives, etc.
I have now idea on how IRIX handled the backup.
/Nico
12:56 p.m.
On 03/23/2015 08:46 AM, Douglas Taylor wrote:
I have a couple of 4mm and 8mm tapes that contain data
I want to
recover. The 4mm is DDS-1 and was written using tar on a SGI system in
1998. My questions are;
'What modern DAT tape drive will read this tape? How backward
compatible is this technology?'
Depends largely on the manufacturer. For example, a QuantumA DDS-4
drive should be backward-compatible. For other brands, check the
manufacturer's specification.
This seems like an easy problem and intend to use a
linux system to read
the tape.
Frankly, it's probably better to use the same software to restore the
tapes that wrote them than trying to suss out the results of a plain dump.
The 8mm tapes were also written on an SGI system, however it was in 1994
and the IRIX Backup utility was used. IRIX 5 was
probably used. Any
ideas?
Exabyte 8mm tapes, like DDS tapes, were pretty good in conforming to
SCSI tape standards, so they should work just tine, provided that you
have the right drive. For 1994, an 8700 should do the job.
Of course, you'll have to deal with the block size issue if these are
not Unix-native, but that's been discussed before here.
--Chuck
9:38 p.m.
Actually, with DDS tapes, you can generally write one gen back and read two. So, a DDS3
drive can read DDS1 and write DDS2.
On Mar 23, 2015, at 10:56 AM, Chuck Guzis <cclist
at sydex.com> wrote:
On 03/23/2015 08:46 AM, Douglas Taylor wrote:
I have a couple of 4mm and 8mm tapes that contain data I want to
recover. The 4mm is DDS-1 and was written using tar on a SGI system in
1998. My questions are;
'What modern DAT tape drive will read this tape? How backward
compatible is this technology?'
Depends largely on the manufacturer. For example, a QuantumA DDS-4 drive should be
backward-compatible. For other brands, check the manufacturer's specification.
This seems like an easy problem and intend to use
a linux system to read
the tape.
Frankly, it's probably better to use the same software to restore the tapes that
wrote them than trying to suss out the results of a plain dump.
The 8mm tapes were also written on an SGI system, however it was in 1994
and the IRIX Backup utility was used. IRIX 5 was
probably used. Any
ideas?
Exabyte 8mm tapes, like DDS tapes, were pretty good in conforming to SCSI tape standards,
so they should work just tine, provided that you have the right drive. For 1994, an 8700
should do the job.
Of course, you'll have to deal with the block size issue if these are not
Unix-native, but that's been discussed before here.
--Chuck
11:53 p.m.
On 03/23/2015 06:38 PM, Roe Peterson wrote:
Actually, with DDS tapes, you can generally write one
gen back and read two. So, a DDS3 drive can read DDS1 and write DDS2.
It really depends. Not all HP DDS3 drives will read DDS1--or so HP claims.
So, it's still best to check beforehand. Or do what I do--keep a mess
of DDS drives of as many kinds as you need. Nowadays, nobody wants the
older ones much, so they can be had fairly inexpensively.
--Chuck
11:59 p.m.
On 2015-03-23 20:53, Chuck Guzis wrote:
On 03/23/2015 06:38 PM, Roe Peterson wrote:
Actually, with DDS tapes, you can generally write one gen back and read
two. So, a DDS3 drive can read DDS1 and write DDS2.
It really depends. Not all HP DDS3 drives will read DDS1--or so HP
claims.
So, it's still best to check beforehand. Or do what I do--keep a mess
of DDS drives of as many kinds as you need. Nowadays, nobody wants
the older ones much, so they can be had fairly inexpensively.
Not every DDS1 drive can read every DDS1 tape. Not every DDS1 tape can
be read in a different specimen of the same model drive as which it was
written in.
I liked 4mm DDS1 tapes for installing software on my PDP-11, but that's
about it.
Zane
24 Mar
24 Mar
4:30 a.m.
On Mon, Mar 23, 2015 at 9:59 PM, <healyzh at aracnet.com> wrote:
Not every DDS1 drive can read every DDS1 tape. Not
every DDS1 tape can be
read in a different specimen of the same model drive as which it was written
in.
I'm not disputing your statement in general, but I've apparently had
better results with DDS interchange than you have. I've used six DDS1
drives from four vendors and three DDS2 drives from two vendors, and
didn't have any interchange problems until one of the DDS1 drives
somehow became seriously misaligned. I believe this must have been the
result of physical trauma causing damage affecting the relative
positions of the head drum and the tape on the vertical axis (along
the width of the tape), or at least with a signifcant component on
that axis, because the track following servo should otherwise be able
to compensate for a fair bit of mechanical variation between drives.
When the DAT and DDS formats were designed, it was intended that they
be robust enough for good interoperation between drives without need
for any manual alignment of individual drives.
Eric
4:32 a.m.
I read somewhere that manufacturers implemented compression and the schemes were
incompatible between drive makers. Perhaps this has caused issues for some..
Dave
G4UGM
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Eric Smith
Sent: 24 March 2015 08:30
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Recovering data from 4mm and 8mm tapes
On Mon, Mar 23, 2015 at 9:59 PM, <healyzh at aracnet.com> wrote:
Not every DDS1 drive can read every DDS1 tape.
Not every DDS1 tape
can be read in a different specimen of the same model drive as which
it was written in.
I'm not disputing your statement in general, but I've apparently had better
results with DDS interchange than you have. I've used six DDS1 drives from
four vendors and three DDS2 drives from two vendors, and didn't have any
interchange problems until one of the DDS1 drives somehow became
seriously misaligned. I believe this must have been the result of physical
trauma causing damage affecting the relative positions of the head drum and
the tape on the vertical axis (along the width of the tape), or at least with a
signifcant component on that axis, because the track following servo should
otherwise be able to compensate for a fair bit of mechanical variation
between drives.
When the DAT and DDS formats were designed, it was intended that they be
robust enough for good interoperation between drives without need for any
manual alignment of individual drives.
Eric
1:32 p.m.
New subject: Recovering data from 4mm and 8mm tapes/ftape advice
On 03/24/2015 01:32 AM, Dave G4UGM wrote:
I read somewhere that manufacturers implemented
compression and the
schemes were incompatible between drive makers. Perhaps this has
caused issues for some..
I do recall, back in my dim memory, that when I was writing software for
the DDS, DLT and 8mm drives, that I would turn off all of extra vendor
features when creating tapes. There were some interesting differences
in the DDS1 drives. And vendor-unique features differed considerably.
Some drives, for example, allowed for read-after-write (i.e. rewriting
of a block), but not all did.
--------------------------
Speaking of tapes, and not wanting to hijack the thread, but does anyone
here have experience with the Linux ftape (floppy tape) drivers? I'm
about to install them on a Debian Woody setup and wonder if there's
anything that I should be aware of. I *think* that Woody was the last
distro before they were dropped altogether.
--Chuck
3408
days inactive
3409
days old
9 comments
7 participants
participants (7)
-
cclist＠sydex.com -
dave.g4ugm＠gmail.com -
dj.taylor4＠verizon.net -
healyzh＠aracnet.com -
nico＠farumdata.dk -
roeapeterson＠gmail.com -
spacewar＠gmail.com