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At 06:01 PM 10/9/96 -0400, Tim Tyhurst wrote: ... >What happens seems to be this: the Thinkpad (or docking station) in which >the drive is installed is responsible for setting the master vs. slave >ID of the drive. On Thinkpad drives, shorting the appropriate pin pair >makes the drive a master. Unfortunately, on some of the IBM drives >(including the DSOA-20180), it's the *absence* of the jumper that makes >the unit a master -- the presence of the jumper makes the drive a slave. > >Now, what I've been doing so far is just using a bit of tape on >the caddy connector to prevent the ThinkPad from erroneously >jumpering the device to be a slave. Of course, this won't work >if the drive is supposed to be a slave (presumably whenever the >drive is in a docking station?) but it works for me right now, anyway. > >-- >Tim Tyhurst tim@excelsior.com > > I want to clarify how you made this work... I checked on the IBM web site for the DCRA22160 drive info (http://eagle.almaden.ibm.com/storage/techsup/hddtech/dcra/dcrajum.htm) and found that, depending on the jumpers of pins IBM identifies as 47, 48, 49 and 50 (but what I have seen as pins 1, 2, 3 and 4 on another drive), the 22160 can be either master, slave, or set by cable connect through Pin 28. It seems that, according to what you have done, you want NO CONNECTIONS between pins 48 and 50 (or 2 and 4 by my reckoning) to make the drive a Master. If those pins are not independently jumperable, but instead are brought out through the caddy cable, they have to be controlled at the caddy connection in the laptop bay. If I read your message right, the caddy connections inside the notebook are preset to jumper pins 48 to 50 on the drive because of some weirdness of IBM's making (incompatible use of those pins from old drives to new drives). You must have traced the caddy cable to find the correspondence between drive pins 48 and 50 to the corresponding caddy pins (?? and ?? -- can you tell us which pins these are?). Then you put tape on those caddy pins to disable the "motherboard" jumper? If that is right, then there is a good chance that the 22160 could be made to work in a 755, which would be nice (at least for me). If someone wanted to make a little money, they could put together or modify one of the aftermarket caddy's to include the option of jumpering those pins independent of the caddy connection. If you have this in the next week for about $60, let me know...though I really prefer to use the IBM caddy to retain the locking functions. Thanks Mike Redmond