> > Back to the original question, then: how much does 100M of disk > > cost? > > 8GB AS/400 disk: $1400 > 20GB IDE disk: $88 > > This doesn't take into account labor/installation charge. Also it should be > noted that the AS/400 disk is 10,000RPM as opposed to the 7200RPM of the > IDE disk. How does the reliability compare? I have been in this business of working on systems with IBM computers since the early 1960's. An IBM hard drive has failed at some place where I worked exactly twice. The first case was at my prior employer, on a S/34 ... the part of the drive that was damaged was mapped so that we knew what things not to do, and business continued on the rest of the stuff for the 2 weeks it took for IBM to solve the problem. The second case was at my current employer, on a S/36 ... the hard drive was 13 years old, I had been making noises about mean time to failure ... with IBM help we mapped damaged area & did extra backups of everything except where the hole was, fortunately only one library involved & the only stuff on that part of the drive was stuff in that library in which I had neglected to back it up for too long. (S/3x backups on gazillian diskettes was so time consuming that each day we backed up volatile stuff used all the time.) Now in the same time period, at the same employers, and in conversation with friends, I have known of scores of cases of hardware failure on PCs in which recovery of the data from the failed systems was either not considered, too expensive, or impractical. There were also several cases of upgrades where the replacement equipment could not access the backup media of the old equipment. The problem was not with the quality of the media, but rather a combination of the speed at which the tape drives were advancing & a lack of infrastructure that we take for granted with IBM stuff. Here are examples of what I mean by infrastructure. I get a call from my paper supplier ... one of their customers got into a crunch with paper supply & they use same kind as we do, can they borrow a couple of our cartons & our supply will be replenished from their next order. Sure. It is nite to know this can go the other way if we ever get in a crunch. In the 1970's I think it was, we did a conversion to our first heavy duty hard disk ... it was multi-platters on a removable pack ... the architecture had 2 fixed drives & 2 removable drives ... prior to that our data base was primarily stored on several million punched cards ... I not remember the precise number now. We were using 80 column cards stored in the drawers that came in a certain style of file cabinet ... 3,000 cards to a drawer. The metal top lip of each drawer was higher than height of cards, so the drawers could be stacked. We used metal doilies ... like low tables on wheels, in which 2 drawers wide could be on the metal braces supporting the wheels & 3 wide on the top of the table, typically stacked 2-3 high ... so each doily had 6-12 trays up to say 35,000 cards per doily. The computer room contained a dozen doilies of the application data used most often, and wall to wall file cabinets containing drawers filled with cards, while other rooms had hundreds more doiles and more file cabinets with cards. So to run some applications in the old punched card era. Figure out which applications in computer room will have to move out to make room for what we are about to do ... those doiles roll down corridor to wherever. Make room for having a cleared doily. Move stuff to that doily from file cabinets in other offices, roll doily, or multiples to computer room & check we have everything we need, arranged so convenient to load in right sequence without big hassle. Check the software, which came in decks of punched cards ... perhaps some worn cards need duplication first. You get the picture. Now a decision was made to move to hard disk a lot of this stuff. The conversion involved taking doilies on the company van, strapped down a bit to avoid any spills in transit, to another customer of IBM that had both punched cards & magnetic tape drives on the big reels, copying the punched cards to reels, then driving to IBM HQ which had a computer that could handle both the reels & the type of hard disk we were getting. That was infrastructure that worked effectively to get our data across realities. Now consider the scores of cases I have witnessed in recent decades or been told about by friends. A PC system backed up on tape, the PC system has to be replaced. The new tape system cannot read the old tapes. Can't you read the old tapes into some intermediate service like we used in the punched card conversion? The PC infrastructure is not yet setup for a type of service we IBM users have taken for granted for decades. Yes it is cheaper, but how does its reliability & infrastructure compare? MacWheel99@aol.com (Alister Wm Macintyre) (Al Mac)
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