benson@odi.com (Benson I. Margulies) (06/03/91)
My 320 has the usual IBM/tandberg 1/4 inch polymorphously perverse tape drive. (anyone know where to get a drive like this that writes both 60 and 150 MB for a sun?) In smit, its configured for 512 byte blocks. I write tapes with backup -i (for consumption of installp). tcopy, documented to report on record sizes, swears that the tape blocks are 65536 bytes long. I think it's lying. Can anyone convince me otherwise? -- Benson I. Margulies
mbrown@testsys.austin.ibm.com (Mark Brown) (06/04/91)
benson@odi.com (Benson I. Margulies) writes: |Path: awdprime!auschs!panews!uunet!uunet!odi!benson |From: benson@odi.com (Benson I. Margulies) |Newsgroups: comp.unix.aix |Subject: 1/4" tape and record sizes |Message-ID: <1991Jun3.024011.387@odi.com> |Date: 3 Jun 91 02:40:11 GMT |Reply-To: benson@odi.com (Benson I. Margulies) |Organization: Object Design Inc., Burlington, MA |Lines: 12 | |My 320 has the usual IBM/tandberg 1/4 inch polymorphously perverse |tape drive. (anyone know where to get a drive like this that writes |both 60 and 150 MB for a sun?) | |In smit, its configured for 512 byte blocks. I write tapes with backup |-i (for consumption of installp). tcopy, documented to report on |record sizes, swears that the tape blocks are 65536 bytes long. |I think it's lying. Can anyone convince me otherwise? My tape expert says: The record sizes reported on by tcopy are not physical tape record sizes but rather the size of the reads and/or writes done by tcopy. Sounds to me like there is a documentation problem, or backup isn't writing things out in the block size you think it is (when in -i). I'm adding it to my list-o-things. DISCLAIMER: Any personal opinions stated here are just that. Mark Brown IBM PSP Austin, TX. | Don't you feel more like (512) 823-3741 VNET: MBROWN@AUSVMQ | you do now MAIL: mbrown@testsys.austin.ibm.com | than you did when you started?
johnson@aixwiz.austin.ibm.com (Fred L. Johnson) (06/05/91)
In article <1991Jun3.024011.387@odi.com>, benson@odi.com (Benson I. Margulies) writes: |> From: benson@odi.com (Benson I. Margulies) |> Subject: 1/4" tape and record sizes |> Date: 3 Jun 91 02:40:11 GMT |> |> My 320 has the usual IBM/tandberg 1/4 inch polymorphously perverse |> tape drive. (anyone know where to get a drive like this that writes |> both 60 and 150 MB for a sun?) |> |> In smit, its configured for 512 byte blocks. I write tapes with backup |> -i (for consumption of installp). tcopy, documented to report on |> record sizes, swears that the tape blocks are 65536 bytes long. |> I think it's lying. Can anyone convince me otherwise? |> |> |> -- |> Benson I. Margulies tcopy is telling you the size of the buffers that it used with its read system calls. I does not report the size of the physical blocks on the tape. What you see in SMIT is the size of a physical block on the tape. The actual buffer sizes used with the read and write system calls need only be multiples of the physical block size. tcopy happens to use 65536 bytes. backup by default uses 100 block (51200 byte) buffers for tapes. - Fred My remarks and opinions are mine alone... ____________________________________________________________________________ | | | | Fred L. Johnson | Internet: johnson@aixwiz.austin.ibm.com | | IBM Personal Systems Programming | inet: johnson@tanstaafl.austin.ibm.com | | AIX BOS Field Quality | vnet: FJOHNSON at AUSVMQ | | 11400 Burnet Road, 994/3401 | phone: (512) 823-4706 | | Austin, TX 78758-3493 | tie line: 793-4706 | |__________________________________|_________________________________________|