bakken@cs.arizona.edu (Dave Bakken) (06/10/90)
In the last week or two it has come out that audio DAT recorders will be available here in the USA as early as September. The prices will start out at $900 and on down, and will likely drop as more models and volume get on the market. Could these guys be used for computer backup? I guess that your are supposed to be able to make perfect copies of a CD. This might imply that there is digital input/output in these beasts (or at least input - or else the CD player would turn the bits into analog, and then the DAT recorder back into digital. Not a perfect copy in my book). If they could be used for this purpose, it seems that it could be cheaper than buying the DATs that are currently available for computer backup, just because of the large numbers involved. Any informed comments would be appreciated. Thanks! -- Dave Bakken bakken@cs.arizona.edu uunet!arizona!bakken U of A Computer Science (602) 621-4098
bruce@nucleus.mi.org (Bruce Lilly) (06/12/90)
In article <21987@megaron.cs.arizona.edu> bakken@cs.arizona.edu (Dave Bakken) writes: >In the last week or two it has come out that audio DAT recorders will >be available here in the USA as early as September. The prices will [...] > >Could these guys be used for computer backup? I guess that your are >supposed to be able to make perfect copies of a CD. This might imply >that there is digital input/output in these beasts (or at least [...] > >If they could be used for this purpose, it seems that it could be >cheaper than buying the DATs that are currently available for >computer backup, just because of the large numbers involved. > >Any informed comments would be appreciated. Thanks! >-- >Dave Bakken bakken@cs.arizona.edu uunet!arizona!bakken >U of A Computer Science (602) 621-4098 1) The (Sony/Philips) digital audio I/O format is quite specific to digital audio applications. You would have to build an interface to/from that format ($$$). 2) Audio DAT recorders are designed for real time record/play operation. They are not start/stop data recorders. 3) (Consumer) DAT recorders generally have no type of control interface, except for a handheld remote controller. Therefore, unattended backups, which are possible with a data recorder with a computer interface, would not be practical. 4) The error concealment used in the event of uncorrectable errors is designed to minimize audible disturbances. For data recording an error flag is desired. 5) Etc., etc. etc. .... The moral(s) of the story is(are): If you want a data recorder, buy a data recorder. and You get what you pay for (or, to be more correct, You don't get what you don't pay for). All of the above apply in principle to digital video recorders as well (so don't ask...). -- Bruce Lilly, Product Manager, Digital Television Tape Recording, Sony Communications Products Company
simons@hpcpbla.HP.COM (Simon Southwell) (06/15/90)
> > In the last week or two it has come out that audio DAT recorders will > be available here in the USA as early as September. The prices will > start out at $900 and on down, and will likely drop as more models > and volume get on the market. > > Could these guys be used for computer backup? I guess that your are > supposed to be able to make perfect copies of a CD. This might imply > that there is digital input/output in these beasts (or at least > input - or else the CD player would turn the bits into analog, and > then the DAT recorder back into digital. Not a perfect copy in my > book). I know that the Sony DAT player (the DTC1000) has digital audio input and output interfaces, based on the AES/EBU interface standard (see "AES recommended practice for digital audio enginering --- serial transmission format for linearly represented digital audio data. J. Audio eng. Soc. 33, 975-984") much like that of the Digital OUT of a CD. I also believe that digital copying of CDs cannot be made since the DATs will won't recognise the 44.1KHz data (DATs nominaly work at 48KHz sampling). This is done only as a copy prevention measure, rather than for any technical reason. Indeed, they now have a "copy code" on pre-recorded material to prevent digital to digital copying of DAT material. All this needed to be done before DATs were allowed in the US. Having said all this, in theory, the Digital interfaces could be used to store and retrieve computer data. There are some drawbacks however, such as . Limited file searching facilities. The "Start" id's for tracks could be used, but you'd have to develop some equipment to decode all this properly. . Inferior error rate. The DAT has 2 levels of error correction, plus an interpolation circuit, for upto 8 uncorrected samples (never heard of interpolated data though :->). The Digital Data Storage drives can offer 3 levels of ECC, plus read-after-write data integrity checking, which in theory give an error rate of better then 1 bit in error every 10^15 bits. > > If they could be used for this purpose, it seems that it could be > cheaper than buying the DATs that are currently available for > computer backup, just because of the large numbers involved. > You are of course paying for all the extra electronics (ie. controller, host interface etc.) on a Digital Data Storage drive, as well as the better data integrity. But I believe that basic SCSI OEM drives sell from around $1200, which isn't much more, and the price of these drives is very much dependent on the audio market, since the Head/mechanism technology is common to both DAT and DDS units. So, I guess using a DAT as data storage is possible, but it may not be worth it in the end. It all depends on the application I suppose. I hope this is helpful. ____________________________________________________________________________ | | | | ####### # ######## | | | ##### #_ _ ##### | Simon Southwell tel: | | #### # # # # #### | (0272)799910 ext.22419 | | #### # # #_ # #### | Research and Development | | ##### # ##### | Hewlett-Packard Ltd. fax: | | ####### # ######## | Filton Road (0272)236091 | | | Stoke Gifford | | COMPUTER PERIPHERALS | Bristol BS12 6QZ e-mail: | | BRISTOL | England simons@hpcpbla.bri.hp.com| |______________________|_____________________________________________________|