Technically there are Inter-Record-Gaps. As far as I know all SCSI and IDE disk are physically formatted in 512 byte sectors (oddly enough so they will work with Windows, which seems to have problems with anything other than 512 bytes). In reality there is a header followed by a gap followed by 512 bytes of data followed by another gap then next header. In gory detail: each header and data block actually starts with a sync mark to get the timing started, then the data or header, then a block of ECC. All of this is hidden by the SCSI or IDE controller (the one on the disk, not the one on the bus).
I know this is probably more then you wanted to know, but I use to work for a company that made disk controllers. -----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] Behalf Of Post, Mark K Sent: Friday, August 12, 2005 1:07 PM To: [email protected] Subject: Re: Dasdfmt and other potential block sizes Speaking as a 20+ year MVS-OS/390-z/OS guy, what business is it of theirs anyway? Besides, I'm not 100% sure there are Inter-Record-Gaps on storage arrays anyway. The 3390 emulation may present them, but I don't think they're really there. Stick with 4096 block sizes. Mark Post -----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of Nix, Robert P. Sent: Wednesday, August 10, 2005 3:34 PM To: [email protected] Subject: Dasdfmt and other potential block sizes I've been letting the blocksize default to 4096 for dasdfmt, but I'm getting abuse from zOS types for not using half-track blocking, and the space I'm losing to IRGs. What are the possible values for the blocksize, and what are the pros and cons of changing away from the default of 4096? Anyone doing this? -- Robert P. Nix Mayo Foundation RO-CE-8-857 200 First Street SW 507-284-0844 Rochester, MN 55905 ----- "In theory, theory and practice are the same, but in practice, theory and practice are different." ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
