[Default] On 18 May 2016 19:31:34 -0700, in bit.listserv.ibm-main [email protected] (Steve Thompson) wrote:
>> snip >Makes one very glad to have things like thumb drives that we have >today. Now if I could just get one big enough to IPL z/OS... Would 128 gigabytes be enough. I think I have seen 256 GB. The software to emulate ECKD would be interesting. Clark Morris > >Regards, >Steve Thompson > > >On 05/18/2016 09:07 PM, Paul Gilmartin wrote: >> On Wed, 18 May 2016 17:50:53 -0700, Charles Mills wrote: >> >>> ... It was indeed a direct access storage device. Not a disk, but DASD >>> nonetheless. Certainly not magnetic tape (though it had a family >>> resemblance!) and certainly not unit record. >>> >> What's the criterion? Max/Min latency ratio? Statistical distribution of >> latency >> between randomly selected records? For tape, it's sort of triangular; for >> DASD >> it has a sort of plateau. >> >> Addressable by block and writable randomly without corrupting other blocks? >> DECtape had preformatted addressable blocks; it held a filesystem with a >> directory. It moved from reel to reel past a stationary R/W head. It met >> some >> criteria for DASD and some for tape; it was both. >> >> -- gil >> >> ---------------------------------------------------------------------- >> For IBM-MAIN subscribe / signoff / archive access instructions, >> send email to [email protected] with the message: INFO IBM-MAIN >> > >---------------------------------------------------------------------- >For IBM-MAIN subscribe / signoff / archive access instructions, >send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
