Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!ukma!rutgers!ucla-cs!admin.cognet.ucla.edu!casey From: casey@admin.cognet.ucla.edu (Casey Leedom) Newsgroups: comp.sys.apollo Subject: Re: Can you swap drive electronics packages? Keywords: Micropolis model 1355 170Mb winchester, drive electronics package Message-ID: <16908@shemp.CS.UCLA.EDU> Date: 18 Oct 88 03:08:03 GMT References: <16692@shemp.CS.UCLA.EDU> <3f0efc45.1032a@hi-csc.UUCP> <3f0f0cea.1032a@hi-csc.UUCP> Sender: news@CS.UCLA.EDU Reply-To: casey@cs.ucla.edu (Casey Leedom) Organization: UCLA Cognitive Science Program Lines: 79 | From: giebelhaus@hi-csc.UUCP (Timothy R. Giebelhaus) | | What you are dealing with is no procedure. That is, there is not | procedure set up at the current time. Thus, there is no knowledge of | what will happen if the entire disk is not swapped. I will forward the | idea of further investigation of separating the electronics and the media | of the drive. | | ... OK, I talked to a technical manager (though this is still an unofficial | piece of news). The reason they swap out the entire unit is: | | 1) Swapping the entire unit makes the hardware fix vendor independent. | That is, a hardware engineer does not have to know who supplied the | drive to service the drive; she can simply replace a 155Mb drive | with a 155Mb drive (not necessarily the same drive). | | 2) Many drives would take too much time to debug. It is much more | efficient to send the entire drive back to the product repair center | where it can be debugged than to debug the thing in the field. | | There is no guarantee that the electronic which was replaced on your disk | is 100% compatible with the disk itself. They may be different revisions | or entirely different. Tim, Thanks a lot for checking into this for us!!! We really appreciate it! However, point 2. is totally irrelevant. As I said in my earlier notes, it only took three minutes to swap the electronics boards. This gives you only three components which need to be swap-tested: the controller sitting in the system bus, the drive electronics board, and the drive itself. This gives you a very easy procedure: 1. Swap controller in system bus. If problem goes away, you're done. Stop. 2. Swap drives. If problem goes away, you've narrowed down the problem: Swap old drive back in and install new drive electronics board. If problem goes away, you're done. Stop. otherwise, it's the media: Swap drive electronics boards back and install new drive. Stop. The extra steps in step 2 only involve about ten minutes worth of work. At the rate we're paying for maintenance, it's definitely justified to save the data on the disk. Your first point is slightly more relevant, but not very. It's a minor point to keep track of what drives are in which machines and just bring the correct type of replacement. Apollo doesn't stock that many 155Mb drives to make this a problem. The only really relevant point seems to be the drive electronics compatibility point in your final paragraph. I'm not aware of any guarantee from Micropolis (or any other vendor) which says that these are standard parts on their drives that who's interface to the rest of the drive won't change with succeeding releases of their drive product. Now, if they *do* make some sort of statement to that effect, I don't think Apollo (or any other maintenance organization) has a leg to stand on in refusing to do the drive electronics swapping. | In the mean time, I would let your service engineer replace the entire | drive unless you are into taking risks. Well, that's what we did. But it was sure nice to have that drive back for the one day with the new electronics package so we could recover the data. I made a back up, we installed the new disk, I reinstalled the OS, I restored the files from the back up, and I lost a day and the people using the machine lost three days in the process. Casey -------- The American public wants to be lied to. They want to be told that they are the envy of the world. They want to be told that things are ok. Dukakis points at the serious problems that must be addressed and proposes some of the hard decisions that he thinks will be necessary. Bush tells us that everything is wonderful. Who's ahead in the polls?