Did you ask him what he though the various distribution tapes were? On 7-track tape you really don't have much choice what to use.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> on behalf of Paul Gilmartin <0000000433f07816-dmarc-requ...@listserv.ua.edu> Sent: Sunday, November 15, 2020 6:06 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Improve OMVS cp performance? On Sun, 15 Nov 2020 16:28:02 -0600, Mike Schwab wrote: >They only had 7 track tapes at the time. > >9 track tapes introduced with S/360 in 1964. >https://secure-web.cisco.com/1g3kTcng6DKLa2wZpjswahVbue_vj3uf2QkkhXiKJmCVFfYS7CwPJCOtzLp6sJGh2jwDBJtf-fQIAfhpg9JoyFjr-NP3GJ49DpgasRSaveY70zBAeUcG96cx9DjCCN7RLPVCYV0a5iunz5SDfQn5nUBPwdAzgTbqxMX_OnnnrbUL7OE0eJTsPrbRH4BSajmMRuFZmnPF6bjm9LjWZhRPwPeokTh9c_ZgD83Nr3egz_aDsyHEFvR8fWZl1pcJuZD_eSGb4o_-LVqZnSkkL72wa2225iWLTRU_R7Lmg5vfQNsInxpKROCItW2KofD7KGBQqfEte6pHmt7jYDvsPEWDAgyA4uUlhNRJ6lYNNRE6AzdSfLrBhnJIaQa1NyExfHakIOcVdnTX_c-_bwT1zHcIr9fhzdLOUcUwlKyrq_rn8c2c-w42RxSz2qvekUt_uRHN0/https%3A%2F%2Fen.wikipedia.org%2Fwiki%2F9_track_tape > Which was no obstacle. There were two modes of I/O to 7-track tapes: TRTCH=T, which mapped each tape frame of 6 data bits plus 1 parity to one 8-bit byte. TRTCH=C, which mapped the 24 data bits of 4 tape frames to 3 bytes I know; I successfully used the latter. I had to argue with ops who tried to tell me that I shouldn't use that; it would corrupt mu data. It didn't. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
