It's probably a habit you could break easier than you think. If you're keeping a 3000 online, either in homesteading or pre-migration mode, you could quit buying something as antique as 18GB disk drives. Taking a minute to consider the payoff might help adjust this habit.
We spoke to an IT manager at a California school district who was heading for a Linux replacement, somewhere down the road, for his HP 3000. One reason for the migration was the price of hardware. Yes, even in the year when HP hasn't built a 3000 for 10 years, original equipment disc is selling. Our IT manager reported his 18GB device had doubled in price.
That's original HP-branded disc, certified to run on an HP 3000. Sounds good, but it doesn't mean much in 2013. If that disk doesn't boot a 3000, or it becomes lost in the 3000 IO configuration -- LDEVs fall off -- who will you complain to? The seller of the disk, perhaps. But there's no HP anymore that knows or cares about the HP 3000 and its discs. So much for vendor warranty or certification.
Your third-party indie support company will do the certification -- let's just call it a check -- on the suitability of a model of drive. Seriously, we can't see why managers would buy system discs that have less storage than a USB flash drive crafted to look like a Despicable Me minion. Buying these is a habit, and one you can break with many SCSI discs out there, selling for under $100.
From what I've experienced, any SCSI disk should work. I got an IBM 4GB drive from someplace, and it wouldn’t work. I put it onto a Unix box (HP-UX, Linux I don't recall) then found that the low level format was a 514 block size, not 512. I had to learn about using "setblock" to reformat the drive. Then, I could install MPE onto it as an LDEV 1.
I have these disks laying around
4GB Seagate ST14207W FastWide SCSI-2 68F
2GB Western Digital WDE2170-007 Ultra Fast Wide 68F
18GB IBM Ultrastar IC35L018UCD210-0 SCSI-LVD/SE U160 80pin
18GB IBM DNES-318350 SCSI-LVD/SE U160 80pin
36GB IBM Ultrastar DDYS-T36950 U160 80pin
36GB Maxstor ATLAS 10K IV U160 80pin
36GB Maxstor ATLAS 10K III U160 80pin
There was a time, perhaps 25 years ago, when 18GB discs not only seemed vast, but they were just a dream. Now the collection of USB sticks shown in the picture above sells for $28 at WalMart and holds 6GB more than that costly HP-branded disc.
If you can move beyond the HP PA-RISC hardware, and onto a virtualized server, you'll tap into the vast universe of such cheap storage. One minion can hold more than an LDEV 1, circa 1993. Back up. If one minion stops working, plug in another on that virtualized, PC-based MPE/iX system.