l...@garlic.com (Anne & Lynn Wheeler) writes: > hardware speed and error correction was going to fixed-sized blocks. You > can see this in 3380 track capacity calculations where record sizes have > to be rounded up, sort of compromise hack given that MVS wasn't going to > support real FBA. The 3380 was smaller fixed-sized blocks ... but not > "true" IBM FBA like 3310 & 3370. 3375 was the first CKD emulated on top > of an IBM FBA (3370) device. 512-byte blocks have prevailed for a couple > decades (IBM 3310 & 3370 and follow-ons ... but also all the other > industry standard disks). There is currently inudstry move to 4096-byte > fixed blocks for improved error correction and track capacity. > https://en.wikipedia.org/wiki/Advanced_Format > http://www.seagate.com/tech-insights/advanced-format-4k-sector-hard-drives-master-ti/
re: http://www.garlic.com/~lynn/2015g.html#4 3380 was actually FBA? and https://groups.google.com/forum/#!topic/bit.listserv.ibm-main/3QSdKeko604 IBM journal articles are behind IEEE membership wall ... have found this detailed description at Google Books (3380 error correcting) https://books.google.com/books?id=cG4Zgb8OqwEC&pg=PA495&lpg=PA495&dq=ibm+3380+error+correcting&source=bl&ots=lMaYN_d94F&sig=o-R202AspjC1Ox09YNcZDb9Ljgc&hl=en&sa=X&ved=0CDgQ6AEwBGoVChMIxpHRg-KmxwIVVluICh1twgJy#v=onepage&q=ibm%203380%20error%20correcting&f=false "which has each subblock consists of 96 data bytes and six first-level check bytes are appended in the form of two interleaved codewords" after discussing details of 3380, it moves into RAID & Reed-Solomon codes ... trivia, I worked with somebody in bldg14 that was awarded the original RAID patent. -- virtualization experience starting Jan1968, online at home since Mar1970 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
