I don't believe I ever worked with 200 bpi tapes, but I did work were we had 8 tape drives 6 were 800 bpi and 2 were 1600 bpi with the optional high speed rewind. I guess maybe byte counts were more important back then..
On Wed, Mar 30, 2011 at 10:45 PM, Schuh, Richard <rsc...@visa.com> wrote: > Round tape reels! Now, that is old. Since I remember them too, we are > both showing our age. Do you remember when the 200 bpi density? > > > Regards, > Richard Schuh > > > > > ------------------------------ > *From:* The IBM z/VM Operating System [mailto:IBMVM@LISTSERV.UARK.EDU] *On > Behalf Of *Tom Huegel > *Sent:* Wednesday, March 30, 2011 8:37 PM > > *To:* IBMVM@LISTSERV.UARK.EDU > *Subject:* Re: DDR Question > > Slight brain fart, I didn't even think of hardware compression duh! I > guess the only real way to to do it is just experimentation. > I still seem to remember a program from long ago, and it may have been a > VSE program, that would tell you how many bytes would go to the tape, in > fact I think it told you how many feet of tape (2400/3400) would be used.. > > Thanks guys. > > On Wed, Mar 30, 2011 at 5:14 PM, Tom Duerbusch <duerbus...@stlouiscity.com > > wrote: > >> If you are doing software compression, then, perhaps use the Pipe DDR >> stage and route it to the "count" stage. >> But knowing how much compression the hardware will do....not obvious to >> me. >> >> However, once you do have a compressed tape, DITTO TMP will tell you how >> much tape the compressed dataset took on the media. >> >> Tom Duerbusch >> THD Consulting >> >> >>> Rich Greenberg <ric...@panix.com> 3/30/2011 4:55 PM >>> >> On: Wed, Mar 30, 2011 at 11:37:00AM -0700,Tom Huegel Wrote: >> >> } That doesn't show the compressed byte count is (would be). The goal here >> is >> } to be able to predict how many tapes I will need to do backups. >> >> If you are doing hardware compression in the tape drive, I don't think >> there is any way for DDR to know the compressed byte count. Software >> compression, yes it would. >> >> I suspect that the easiest way to determine the tape counts will be >> experimentally. >> >> -- >> Rich Greenberg Sarasota, FL, USA richgr atsign panix.com + 1 941 378 >> 2097 <%2B%201%20941%20378%202097> >> Eastern time. N6LRT I speak for myself & my dogs only. VM'er since >> CP-67 >> Canines: Val, Red, Shasta, Zero & Casey (At the bridge) >> Owner:Chinook-L >> Canines: Red & Cinnar (Siberians) Retired at the beach Asst >> Owner:Sibernet-L >> > >
