FOWBLE%OHSTPHRM@PUCC.PRINCETON.EDU (Jack Fowble) (09/12/90)
The bottom line question first: If I write on a DC600A cartridge using vendor A's stated 60MB drive unit and adapter, what's the likelihood that I can get an intelligible(?) byte stream into my 4D70GT (with the Cipher 540S 60 MB unit), say using 'dd'? (I'd expect we'd have to play with byte ordering, data formats, etc.; but would we get past blatant low level I/O errors/incompatabilities?) More specificly, Archive has a PC tape unit they call Fastape (60MB) (not the Viper 150) that uses DC600A. Users would like to pull spectra and image data sets from those tapes to the SGI. More generally: Haven't had a good go-round about tape formats and "standards" since last May on this list ;-), at which time I shrugged and thought how lucky I was not to have to think about such madness! Sigh. :-( Looking around here, I find QIC-24 units (seem to do 60MB), QIC-02 units that are also described as QIC-24 (signal interface versus data format???), QIC-150 (150MB) that are also described as QIC-02. The archives of this list also introduced QIC-120 & QIC-11 "standards" (whatever MB). The Fastape unit mentioned above was suggested to me to be of a QIC-36 persuasion. Catalogs indicate QIC-40, -60, -80, and -100 that seem to cross back and forth between standard and mini cartridges. So, WHO writes all these "standards"? Where are such "standards" documented? Anybody already sort all of this out, maybe have some sort of a master reference list? Or does one call in a QIC con$ultant? (As an aside, I even noted a mail order ad describing a flavor of mini cartridge (DC2000) adhering to the "QIC-2000" standard. Oh, come ON now...) In the QIC-sand, Jack
phil@BRL.MIL (Phil Dykstra) (09/12/90)
There are QIC numbers that refer to many things, not just the recording format, but also the interfaces, read/write heads, ECC and Data Compression standards, etc. Don't worry about QIC-02 for example, it is an interface standard. The major recording formats you will see now are: Recording Format Cartridge Type Capacity Read Compatibility QIC-24 DC600A 60MB QIC-120 DC6150 125MB QIC-24 QIC-150 DC6150 150MB QIC-120/QIC-24 (or a longer tape) DC6250 250MB A DC600A cartridge, written in the QIC-24 format, should be readable on any QIC-24, 120, or 150 drive. There may however be the issue of byte swapping (fixable with either dd conv=swab or the SGI "ns" device). Ignore QIC-40, 80, 100, 110, 128, and 380. I believe that these all use a physically slightly smaller cartridge (I don't know who uses them). In fact these cartridges all have numbers in the DC2000's which you mentioned seeing. Long ago, Sun used to use QIC-11 by default (a lower density format even than QIC-24) and /dev/rst8 would get you QIC-24. QIC-11 is now old enough that it no longer appears on my cheat sheet. And the one other QIC number you asked about: QIC-36 is the Basic Interface standard for QIC-24 format drives. No doubt it is all designed to confuse the consumers. - Phil