Anne & Lynn Wheeler <[EMAIL PROTECTED]> writes: > i apologize that i've not done what you have instructed me to do. > maybe you should also try ordering some number of other people to also > answer your questions.
reference: http://www.garlic.com/~lynn/2007f.html#3 FBA rant part of the reason that i don't really know the definitive answer to your question is that BB in BBCCHH may have been planned for a number of related products ... besides the 2321. i have some vague recollection of discussions related to 1360/pdss which may have also motivated the inclusion of BB in 360 ckd dasd architecture; i.e. even if 2321 hadn't shipped ... the decision to include BB may have been made assuming a variety of products that might use it. in this 1360/PDSS reference http://en.wikipedia.org/wiki/IBM_1360 it mentions having a total capacity of 2,250 "cells" possibly helping motivate two digit BB field (as opposed to ten 2321 cells) under some assumption that such devices might also eventually appear attached to 360 channels. this may have also contributed to the DASD acronym for direct access storage device ... because of the variety of storage technologies that were being used in the period (not just disk and not just magnetic). the above article implies that 1360 saw limited deployment, in part because of various follow-on magnetic related storage devices like 3850 (however, it doesn't mean that the senior engineers hadn't originally anticipating that such devices might be attached to 360 channels). 3850 reference http://en.wikipedia.org/wiki/IBM_3850 there is mention in the above that the tape cartridges originally were to be directly addressed ... possibly also using BB specification ... but it was eventually changed to the virtualized 3330 implementation. So there is possibility that 3850 originally was envisioned as (also) being much more of a 2321 kind of operation (having up to 4720 cartridges ... possibly also fitting into the BB specification). past posts in this thread mentioning 2321: http://www.garlic.com/~lynn/2007e.html#38 FBA rant http://www.garlic.com/~lynn/2007e.html#51 FBA rant http://www.garlic.com/~lynn/2007e.html#63 FBA rant http://www.garlic.com/~lynn/2007e.html#64 FBA rant http://www.garlic.com/~lynn/2007f.html#0 FBA rant part of the issue is all of the senior people that would have likely been involved in thinking about justification for including "BB" as part of the standard architecture were gone by the time i showed up. the senior people having moved on was also the excuse given for periodically calling me in to play disk engineer ... recent posts mentioning periodically getting called in to play disk engineer: http://www.garlic.com/~lynn/2007b.html#28 What is "command reject" trying to tell me? http://www.garlic.com/~lynn/2007e.html#40 FBA rant http://www.garlic.com/~lynn/2007e.html#63 FBA rant lots of past posts mentioning getting to play around in dasd engineering lab (bldg 14) and dasd product test lab (bldg 15) ... sort of across the street from sjr in bldg. 28. http://www.garlic.com/~lynn/subtopic.html#disk ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
