jbs@mit-eddie.UUCP (03/07/86)
References: I recently posted a request to net.unix-wizards about running a Cipher 880 (1600 bpi) tape drive on a Unix (4.3 BSD) VAX-11/750. The basic problem was that it is a streaming drive and if it doesn't get data fast enough, it goes into something Cipher calls start-stop emulation mode. When this happens, the drive constantly stops, repositions, and continues writing. The performance in this mode is horrible. Well, I've gotten lots of information about how to keep the tape drive in streaming mode (I'll post a summary to net.unix-wizards soon). The Cipher documentation indicates that the drive can operate at 25 ips and 100 ips. I don't see anywhere how one configures the drive to run at the higher speed. Now it is running (and streaming) at what appears to be 25 ips. How can I get it to go into 100 ips mode? Is this, like the start-stop mode, automatic (i.e. I get Unix to spit out data even faster and the drive starts spinning faster) or is there something I must do to the drive and/or controller? Thanks for any information or suggestions. BTW, is Cipher Data Products on the net? Jeff Siegal - MIT EECS
cdl@mplvax.ARPA (Carl Lowenstein) (03/11/86)
In article <1206@mit-eddie.MIT.EDU> jbs@eddie.UUCP (Jeff Siegal) writes: >I recently posted a request to net.unix-wizards about running a >Cipher 880 (1600 bpi) tape drive on a Unix (4.3 BSD) VAX-11/750. > >The Cipher documentation indicates that the drive can operate at 25 >ips and 100 ips. I don't see anywhere how one configures the drive to >run at the higher speed. Now it is running (and streaming) at what >appears to be 25 ips. How can I get it to go into 100 ips mode? The signals from the controller (host adapter) to the tape drive include 'IHISP' = High Speed Select. (Connector P2, pin 50). Somehow, you must get your controller to assert this line. Frequently it is wired to bit 2 of the unit select, so that drive 4 becomes the high-speed version of drive 0. Look at the controller documentation, and shudder at the thought of yet another /dev/rmtx. -- carl lowenstein marine physical lab u.c. san diego {ihnp4|decvax|akgua|dcdwest|ucbvax} !sdcsvax!mplvax!cdl
mlr0@bunny.UUCP (Martin Resnick) (03/13/86)
> The Cipher documentation indicates that the drive can operate at 25 > ips and 100 ips. I don't see anywhere how one configures the drive to > run at the higher speed. Now it is running (and streaming) at what > appears to be 25 ips. How can I get it to go into 100 ips mode? Is > this, like the start-stop mode, automatic (i.e. I get Unix to spit out > data even faster and the drive starts spinning faster) or is there > something I must do to the drive and/or controller? > Your tape controller must tell the drive to operate at 100ips by asserting the signal IHISP. Your software must tell the controller to assert this signal. Does your driver support this? It could be done with an IOCTL or via the minor device number.