Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!sdd.hp.com!hplabs!otter.hpl.hp.com!hpltoad!hpopd!hpcpbla!kev From: kev@hpcpbla.HP.COM (Kevin Jones) Newsgroups: comp.periphs.scsi Subject: Re: sync scsi tape drives (non 1/2 inch) Message-ID: <9850014@hpcpbla.HP.COM> Date: 18 Feb 91 07:34:01 GMT References: Organization: HP Computer Peripherals Bristol, UK Lines: 31 > The average data rate is, of course, determined by the tape speed > and bit density. True for 1/2" technology. For 4mm and 8mm tape drives things get a bit fuzzy due to the ECC and format information embedded alongside "user" data. Also, for various reasons, these drives can "pad" data, further "diluting" the recording density (from the users viewpoint). In these cases, its no longer accurate to derive data rate by multiplying bit density by tape speed. From an overall "throughtput" standpoint: it is not uncommon that the "bottleneck" for the data rate to tape is the system itself. The speed of the disks, the power of the processor, the number of other things you're trying to do at the same time, and the amount of format information your "smart" backup application has to inject into the data stream can slug throughput such that the drive starts streamfailing. ----------------------------------------------------------------- Kevin Jones. | Hewlett Packard Ltd, | Computer Peripherals Bristol, kev%hpcpbla@hplb.hpl.hp.com | Filton Road, | Stoke Gifford, Tel: 011 44 272 799910 (ext 22351) | Bristol. BS12 6QZ. | ENGLAND. ----------------------------------------------------------------- This response does not represent the official position of, or statement by, the Hewlett-Packard Company. The above data is provided for informational purposes only. It is supplied without warranty of any kind.