In a command channel program, you can chain any number of CCWs together, each of which can possibly transfer up to X'FFFF' bytes. It's theoretically possible to have one very long chain that copies an entire EVA DASD to somewhere else in only one I/O request; i.e., only one SSCH. You would need a lot of real storage and billions of CCWs, but it's theoretically possible. Bill Fairchild
----- Original Message ----- From: "Scott Ford" <[email protected]> To: [email protected] Sent: Monday, December 9, 2013 10:53:03 AM Subject: Re: "hexadecimal"? Bill, I thought you could chain ccws Scott ford www.identityforge.com from my IPAD 'Infinite wisdom through infinite means' > On Dec 9, 2013, at 10:42 AM, DASDBILL2 <[email protected]> wrote: > > Channel programs have always been able to transfer anywhere from zero to > 65,535 bytes per CCW. Most access methods do not support any CCW byte count > greater than approximately 32K. > To render my first sentence more up-to-date, I should say channel programs > running in command mode have always been able... etc. (since transfer mode > channel programs have no CCWs in them). > > Bill Fairchild > Franklin, TN > > ----- Original Message ----- > > From: "Paul Gilmartin" <[email protected]> > To: [email protected] > Sent: Sunday, December 8, 2013 8:25:50 PM > Subject: Re: "hexadecimal"? > >> On Sun, 8 Dec 2013 20:01:20 -0600, Joel C. Ewing wrote: >> >> If the real requirement is that the parameter address must point to a >> location containing what the PoOp describes as a half-word binary value, >> then the manual should state precisely that. >> > Thanks for bringing this thread back to my original concern when I > started it (I never imagined! ...), however interesting the digressions > to HFP and ternary logic may be, and for stating that concern more > clearly than I did. > > There should also be mention of the allowable range of values: > 0<n<=32760? 0<n<=BLKSIZE? 0<n<track-size? 0<n<=65535? > (The last is the maximum supported by channel programs, or was.) > Are unsigned halfwords supported? This became an issue about the > advent of the 3380. > > Clearly the present text of the manual engenders confusion and > dissent. > > -- 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 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
