I have these comments in my REXX TAPESTAK program: /* */ /* Add in the Inter Block Gaps (IBG) */ /* */ /* The density of a 3480 cartrige is: */ /* 1491 characters per millimeter American National Standard */ /* */ /* 1 inch = 2.54 centimeters or 25.4 millimeters */ /* 1 character = 1 byte */ /* 1491 * 25.4 = 37871 bytes per inch (38K BPI) */ /* */ /* The IBG is .08 inches */ /* 37871 * .08 = 3030 bytes */ /* */
Mark -- Mark Zelden Sr. Software and Systems Architect - z/OS Team Lead Zurich North America / Farmers Insurance Group: G-ITO mailto:[EMAIL PROTECTED] z/OS and OS390 expert at http://searchDataCenter.com/ateExperts/ Systems Programming expert at http://expertanswercenter.techtarget.com/ Mark's MVS Utilities: http://home.flash.net/~mzelden/mvsutil.html On Sat, 28 Apr 2007 20:55:31 -0400, John S. Giltner, Jr. <[EMAIL PROTECTED]> wrote: >I found a few references to some 3490E talking about the recording >density of 37,871 BPI > >http://www.sunstarco.com/Tape%20Drives/Overland%20Data/Overland%20Data%20tapexpress_l490e.htm >http://www.archives.gov/records-mgmt/initiatives/transfer-regulation.html >http://webstore.ansi.org/ansidocstore/product.asp?sku=ANSI+INCITS+180-1990+(R2006) > >There were many more. > >I wonder if the differnce of 32K and 38K is user data vs user data >+parity. > >Rich Smrcina wrote: >> So are you saying that Ditto lies? >> >> R.S. wrote: >> >>> Robert Pelletier wrote: >>> >>>> Hi All. Question. Would anyone know the BPI of a 3480 cart running on >>>> 3480E drive (mock 3490). We have a request from a user to send us a >>>> 38,000 bpi cart. I swear they are 6250 bpi. Can anyone clear this up for >>>> me? Where are they getting the 38,000? Thanks once again all. >>> >>> >>> >>> Back to the question: CST cartridge contains 160m of tape. >>> Uncompressed capacity in 36-track drive (3490E) is 400MB. >>> So 400MB/160m gives 25000 B/cm Inch is 2.54 cm, so the BPI is 63500. >>> CST in 3480 drive has 31750 BPI. >>> >>> The values above are without compression. >>> I don't know exact length of tape and exact capacity, maybe it's not >>> exactly 160m, however it seems the BPI can be approx. 32000. It rather >>> cannot be 38000. > ---------------------------------------------------------------------- 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
