Mr Ian Primus wrote: Aha... interesting. I'll give local Freecycle a prod and see if anyone has one nearby that I can borrow. What with Andy's post and another offer off-list I expect I can attempt a read at some point, anyway! That's good to hear. They reminded me of big DAT tapes, and I've had some pretty nasty experiences with DAT in the past :-) Well as I'm not sure what's even on them - and whatever is on there is probably something very dull - I'm not too fussed if they turn out to be unreadable. I just figured I should make an effort to at least try! cheers J.

On 9 May 2007 at 13:52, Jules Richardson wrote: If it's like the 8510 that I had, it's SE--note that it's not auto- terminate (you'll need a SCSI terminator). In my eperience, the drive was buggy and TTi itself is defunct. You may have better luck with a genuine Exabyte 8500. The TTi unit isn't quite old enough to suffer from roller goo yet, so it's hard to say if it will eventually. Tell ya what, stick it in a room with one of those electronic air ionizers and get back to us in 6 months.. :) Cheers, Chuck

On 9 May 2007 at 15:30, Jules Richardson wrote: My recollection is that there were numerous firmware bugs. We'd received the drive as a sample in order in hope that we'd endorse it as a drive to work with our software. It didn't work as expected, TTi fessed up to some firmware problems and we told them to get in touch with us when they got things ironed out and sent the drive back. Which is better than the trick that Datasonix pulled with its Pereos drive. They sent us a sample to evaluate. It took us about 2 hours to determine that it wasn't ready for prime time and shipped it back (although I probably still have the drivers for it). It was not only slow and unreliable, but it was brain-dead, requiring a driver that was something like 100K (MS-DOS) in size. Datasonix went ahead and told a customer that we'd approved it--and the customer bought 150 of the worthless things before they checked with us. Isn't most of the rubber used in QIC drives just neoprene? To me that says anything using it will eventually have goo problems. How about old printers with neoprene feed rollers? Cheers, Chuck

On 10 May 2007 at 16:25, Jules Richardson wrote: "Slow" is a relative term. Back in the day, they weren't too bad, compared to, oh, say, floppytape (QIC 40). Cheers, Chuck

Mr Ian Primus wrote: Heh, it was too. Someone had only bothered to tick off two of the cycles on the tape itself, but stupid me hadn't bothered to check the physical tape inside :( I'm only getting just over 20KB/s out of the drive though, so I'm trying to trace the problem there at the moment - I gather transfer rate should be more like 15 times that value. Unfortunately the 'net seems to be populated with people who want dip switch settings for this (TTi, not the internal Exabyte drive) unit, but nobody who actually has them. I've ruled out SCSI problems (at least with the HBA, cabling and termination), so it looks like the drive itself really is only spitting data out that fast. mt's status isn't reporting any errors, nor are the SCSI logs, and nor is the front panel of the drive... A 31 hour restore if there's 2.3GB of data on the tape is a bit on the lengthy side...

Pete Turnbull wrote: I'm not sure. It's logged as connected with a user speed of 10MB/s, but "goal" and "current" speeds of 3.3MB/s. But still, 3.3MB/s is a long way off 21KB/s - even allowing for SCSI protocol overheads :-) It certainly didn't say at boot time that it was async, anyway. The TTi adapter board inside the drive seems to be an interceptor mainly for the front panel - SCSI in from the HBA on the one side, then SCSI out to the Exabyte EXB-8500 drive on the other. In other words, I don't know of a way of seeing what the bus between the intercept board and the drive itself is doing - it's quite possible there's a problem there. Unfortunately the EXB-8500 drive seems to have been modified firmware-wise as part of the TTi setup; it refuses to talk direct to the HBA and doesn't even show up in an inquiry at boot time. Looks like it'll *only* cooperate with the TTi intercept board. Either that or it's utterly, utterly broken. The only other possibilities are the unknown jumpers on the back of the main unit are running the drive in some sort of restricted mode, or there's some weird vendor-unique command that needs to be sent to the drive to kick it into high gear. If someone has a known-working one of these TTi units and can at least quote me their jumper settings off the back, that would be useful! 10-12 control the SCSI ID (as someone's scribbled that on the drive in pen), but I have no idea what the other 9 are for. If it comes to it, I'll just leave the thing running for a day and a half...

Chuck Guzis wrote: Well all was not lost as it turns out - that first tape only contained 160MB of data out of a possible x GB, so it's finished! I'm not getting anything out of the other tape though - I can't even drag any raw data off it using dd, which I would have thought should be possible. Either the tape's broken or the drive just plain doesn't like it for some reason (this is the proper data cartridge too - it was the backup to video tape that's read successfully) Yep.... It looks like TTi went to a lot of trouble / expense to turn a reliable drive into an unreliable one, all for the sake of a bit of front-panel status info :-( cheers J.

TTi finally went belly-up? Quoting Chuck Guzis <cclist at sydex.com>:

I have a TTI tape drive somewhere, it's got 2 8510's in it and an LCD display on it. looking in it before it was standard exabyte 8510's with their special controller board connected to them IIRC. Quoting Jules Richardson <julesrichardsonuk at yahoo.co.uk>:

--- "Roy J. Tellason" <rtellason at verizon.net> wrote: Not quite. Those drives are probably too new - the Exabyte Mammoth drives. Those can hold 20 gb on a tape, but require different tapes - AME instead of the MP tapes. AME stands for Advanced Metal Evaporated or something, as opposed to Metal Particle tapes like those used for video. The MP tapes won't work and will most likely clog up the heads on a Mammoth drive. The 8200, 8500, 8505 and 8700 drives take MP tapes, the 8900 and newer take AME. Somewhere along the line I think they changed them again though. Yes - there is a chance they're the older 8505/8505c drives that can do 7 gb or 14gb compressed using 160m MP tapes. The older drives (8200/8500) were full height. -Ian

Chuck Guzis wrote: That's good to hear :) I tend to put stuff on DLT still - unless it's something really large (like a raw archive of some vintage system's hard disk), in which case it gets mirrored to a second hard drive. I always figure there's a lot less to go wrong in a DLT cartridge than there is with a hard disk - but I'm not sure how it all works out in the end given that the physical data surfaces in a hard disk are probably more robust. Maybe the clever thing to do would be to backup twice to two *identical* hard drives, in the hope that if either the logic board or the "mechanical" side went wrong there'd be enough good bits to make up a working unit from which to restore. (Note that I'm talking "home backup" here rather than corporate... I think generally what happens though is that 99.9% of the world's home users don't actually bother backing anything up at all)

Yeah, I can't ever remember seeing 4mm audio DAT tapes used for data either. I was under the impression that they would stretch or something. It could also be that since the audio DAT format didn't really take off at all in the consumer field, that the data tapes would have been more available. I routinely use video 8mm tape with the Exabyte 8200 drives, because I can't find the 8mm data tapes locally - but I can buy video cartridges at the grocery store (and they're frequently on sale!). I've never had a problem with video tape in those drives. -Ian

I don't have any audio DAT tapes, so I can't say for certain, but I do have an audio DAT deck - it works just fine with the computer data tapes. Never tried it the other way around. I think the dots are just to differentiate between DDS1, 2 and 3. I remember once I tried to modify a DDS2 cart to become a DDS3, to see what would happen. It didn't work. (gee, surprise, surprise)... -Ian

This is something that worries me a lot! I have lots and lots of irreplaceable content and don't want to see it vanish. What can I TRUST today for some two terabytes of data? Please, cheap options, I still cannot afford a DLT :o)

So try to find that (at that price, hehe) in Brazil... :o(

Yes, but there are lots of variables on this thing: - International credit cards are not so common in Brazil. Myself, as an example, I don't have one. No paypal therefore. - Not all sellers ship international. Dunno why. Lots of things I tried to buy on EBAY before were denied because of international shipping - no matter how expensive or cheap it would be - In Brazil, believe it or not, we still have heavily taxing of anything abroad. It is a game of luck. Or no luck. A DLT drive can pass thru (it almost always happens) or be taxed as a new $5000 DLT drive. 60% on the price + shipping. Buying things in USA is an adventure for all of us. Why do you think I don't have simple things as a Speccy or a BBC, or an Atari 512/1024? Well, at least we have good beaches and nice sun ;o) As sad as it can be, these are the rules :o( Greetings from Brazil Alexandre http://www.tabajara-labs.com.br

Hi Dave! I'm not in a hurry, although using the method I told you seems simple enough, I always buy chips from USA getting that via airmail ;o) <more-or-less-offtopic mode ON> (first of all, please sorry me if I use any inappropriate terms on this message. Please advise me if I did. Remember english is not my maiden language) The brazilian girls are as beautiful and gorgeous as the american ones, or the japanese ones or the (hmmmm!) german ones. What matters are the "differences". Germans use to come to Brazil to marry black girls (a half-bred between white and black, which is called "mulata"). In Brazil they are very common, but very rare in Germany. So the germans get crazy with the black girls. Brazilians get crazy with the german girls. It is very rare to find a **natural** blonde girl with (beautiful!) blue eyes. And japanese girls are as beautiful! It is just a matter of "rareness" like our hobby!!! The Brazilian TK90X is **the same** computer as the Sinclair ZX Spectrum. Even the case is the same, but with a small (and better!) ROM containing the UDG2 char editor. But I'd love to have a speccy, just because **it is different**. In the same way, TK90X is a very common computer here, but which Speccy collector doesn't want to have one of these? Just because - as always - is DIFFERENT. Our passions are fueled by differences. The capability to have something that is different from usual, rare or expensive. There are lots of fast cars. A friend of mine had a Saveiro (google image for it, is a very small pick-up made in Brazil by VW) which had some 600HP (!!!) and in dragster racing always won against ferraris! No one want to pay R$ 70.000 to have a Saveiro modded for 600HP, but everyone wants a Ferrari that costs R$ 600-700.000. Because it is different. It is rare. It is expensive. The same happens with girls. The same happens with computers :o) So, don't think our girls (and rare computers) are better than yours, ours are just different! :o) <more-or-less-offtopic mode OFF> Greetings from Brazil Alexandre (Which would love to date an american girl, they are beautiful!)

Hi, I'm sure that the OP is correct about the media recognition system....BUT.... ;-) I've just gone and fished out three of my DAT cassettes (two 90min [one Maxell, one TDK] and one 46min Maxell). Comparing them with the 60 meter HP DDS1 tape I still have lying next to my PC, the pattern of "media recognition" holes is 100% identical on all 4 tapes (in position AND depth). Go figure...? Maybe HP did things "their way"? TTFN - Pete.

On 8 May 2007 at 17:50, Pete Turnbull wrote: I should have put Pereos 2.5 mm media after QIC. I'll wager that audio cassette is more reliable. I think there's an explanation for that. DDS tapes typically have an "ID Burst" recorded right at BOT, which is supposed to tell the drive what kind of tape it is. Some older 4mm drives could get by without the burst, but later ones required it (i.e. wouldn't load the tape). Stick a new DDS tape into your DAT drive and you can usually hear the (caution: very loud) burst--at least I can on my Sony DAT. The other reason is that RIAA fought DAT in the USA tooth and nail to prevent importation of DAT equipment with the result that DAT was fairly rare in the USA. It was much easier to find DDS media than DAT media. I've had decent experience with MO media, but miserable experience with the equipment. In particular, the 4.3G Pinnacle Apex drives would quit functioning for no apparent reason. At one point, Pinnacle had a swapout policy that they would give you a refurb drive in exchange for your bad drive and $300. I remember calling them to arrange the swap and being told that they had an 8 week backlog of bad drives. I borrowed a drive and copied my MO carts to hard disk and recycled the Apex drive. Cheers, Chuck

Personally I'd rate it a bit different. DLT > 4mm DAT > QIC > 8mm I don't remember ever dealing with Travan, though I think I have a couple drives in the collection I've built at work. Zane

At 6:41 PM -0700 5/8/07, Mr Ian Primus wrote: Sorry, no one is going to get me to agree that 8mm is better than 4mm DAT. Though I would put it ahead of 4mm DDS1 DAT. No, I think you're right. I've had some horrible experiences with 9-Track tapes on a Honeywell DPS-8 Mainframe, but other than all those drive issues, I've found 9-Tracks to be the best out there. Actually if we're going with this age range of tapes, from everything I've heard, I'm sure those that have used them would like to put DECtape (TU-56) ahead of 9-Track, of course DECtape-II's (TU-58's) would likely be around the bottom. Zane -- | Zane H. Healy | UNIX Systems Administrator | | healyzh at aracnet.com (primary) | OpenVMS Enthusiast | | MONK::HEALYZH (DECnet) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | PDP-10 Emulation and Zane's Computer Museum. | | http://www.aracnet.com/~healyzh/ |

On Tue, 8 May 2007, Dave McGuire wrote: Amen. My experiences with 4 & 8mm rotary-head units have been abysmal. The Exabyte drives, in particular, just seem to randomly drop dead without warning. And, as others comment, the 1/2-ht. front-loading Exabyte drives are a mechanical nightmare. They make the worst 80s vintage VCR load mechanism look downright simple to repair. The majority of my backups are made on DLT IV tapes using DLT7000 series drives (mostly Compaq and HP OEM units). If you have the latest firmware flashed, they are incredibly solid. In some cases, used tapes require a heroic amount of bulk erasing before they can be reliably written. I have heard this is a result of them being previously used on lower-density drives, but have no proof of this. One of the coolest features of DLT is that they are self-aligning. The drive goes through an intricate dance during tape load to teach the head servo where each track center is. I believe they are capable of re-training during operation if things are found to drift. Also, someone in this thread mentioned that DLT IV was not a read-after-write medium. Is that really the case? I have seen drives throw errors when trying to write damaged media. If they don't do a read-back, how would they know? Another personal favorite is the late Onstream linear tape drive. I have an ADR2 120GB external SCSI drive that just keeps on ticking. Media is getting tough to find, but occasionally I score a few cartridges on ebay. For reasons unknown, the 1/2 size 60GB ADR cartridges do not work at all in these drives. The 120s have never given a problem. These units do not seem to perform a read-after-write, but I've gotten in the habit of making a second verification pass on the tape before considering a backup complete. Steve --

Zane H. Healy wrote: I definitely wouldn't rate DAT/DDS anywhere near that highly. I've found that 8mm tapes are fine if you don't write over them again and again. I can't say the same for DDS. Peace... Sridhar

Zane H. Healy wrote: That's what I mean. I usually can't read DAT tapes that have been sitting on the shelf, even if they were new when first written. The only 8mm tapes I couldn't read were the ones that were written and written and written. Peace... Sridhar