I think Tony was looking for a way to do it transparently, so that no changes were needed to the programs reading or writing what they see as a real tape. Your approach requires modifying the host program or jobstream.
On Mon, Aug 1, 2022 at 8:58 AM Joe Monk <joemon...@gmail.com> wrote: > I dont even understand what the problem is. > > AWS is simply a disk format for a sequential file of tape blocks. What is > inside those blocks are for the program that reads/writes them to decide... > AWS does not decide that. You can easily compress, slice into blocks, and > write to AWS. > > Sam Golobs article on AWSTAPE makes that pretty clear ... > https://www.cbttape.org/awstape.htm > > Joe > > On Mon, Aug 1, 2022 at 7:59 AM Seymour J Metz <sme...@gmu.edu> wrote: > > > Why is IDRC compatibility an issue when you're not using a physical > > cartridge or physical drive that supports IDRC? If you modify AWS to > > support compression, use whatever format that gives you the best results. > > > > > > -- > > Shmuel (Seymour J.) Metz > > http://mason.gmu.edu/~smetz3 > > > > ________________________________________ > > From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf > > of Tony Thigpen [t...@vse2pdf.com] > > Sent: Saturday, July 30, 2022 12:45 PM > > To: IBM-MAIN@LISTSERV.UA.EDU > > Subject: Re: AWS and IDRC/compression > > > > I am working with my VTA vendor to reduce storage usage on the > > appliance. Currently, they can compress after the unmount and uncompress > > before the mount. But, this takes time, especially when servicing the > > mount request if the tape is large. > > > > I was thinking that doing an IDRC implementation, which is stream based > > and performed during write/read, it might be faster even if it's not > > compresses as much as with their current method. > > > > But, if the AWS file is not compatible with IBM's implementation, then > > it's going to add a step to send them the file. The current compressed > > files can be uncompressed using standard linux tools. > > > > Tony Thigpen > > > > Jay Maynard wrote on 7/29/22 22:44: > > > I'm curious. What are you trying to accomplish with it? If it's just a > > > matter of faster transmission of entire tape images, AWS tapes compress > > > very well. > > > > > > On Fri, Jul 29, 2022 at 8:38 PM Tony Thigpen <t...@vse2pdf.com> wrote: > > > > > >> Yes. But, it sounds like nobody else will support it as a data > > >> interchange, so it may be unusable for us. > > >> > > >> I will go look at it. > > >> > > >> Tony Thigpen > > >> > > >> Jay Maynard wrote on 7/29/22 06:38: > > >>> Are you talking about the tape data being compressed inside the AWS > > >> image? > > >>> Hercules has a format that does this, upwardly compatible with AWS, > > >> called > > >>> HET (Hercules Emulated Tape), but I don't know of any other > > >> implementations > > >>> of it. Each block is compressed after being received from the program > > >>> writing the tape but before being written to the file and > uncompressed > > >>> after being read but before being returned to the program reading the > > >> tape. > > >>> > > >>> On Fri, Jul 29, 2022 at 3:56 AM Tony Thigpen <t...@vse2pdf.com> > wrote: > > >>> > > >>>> Does anyone know of any 'standard' for stream based (during file > > >>>> creation) compression of AWS tapes? > > >>>> > > >>>> Tony Thigpen > > >>>> > > >>>> > ---------------------------------------------------------------------- > > >>>> For IBM-MAIN subscribe / signoff / archive access instructions, > > >>>> send email to lists...@listserv.ua.edu with the message: INFO > > IBM-MAIN > > >>>> > > >>> > > >>> > > >>> -- > > >>> Jay Maynard > > >>> > > >>> > ---------------------------------------------------------------------- > > >>> 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 > > >> > > > > > > > > > -- > > > Jay Maynard > > > > > > ---------------------------------------------------------------------- > > > 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 > > > > ---------------------------------------------------------------------- > > 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 > -- Jay Maynard ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
