Solid state drives for HP 3000s?
May 21, 2009
Drives that don't need to spin? These are the Solid State Drives (SSD), a wad of RAM big enough to act like a traditional (but small) storage device. SSDs are now the talk of the Windows and Linux communities, groups which float like butterflies among the diverse fields of hardware. The HP 3000 has prospects to gain SSDs, too.
A technical leap from SCSI storage devices to cutting-edge hardware would be a life-extender for the 3000 users. One tech wizard who's investigating it certainly has the chops to pull off the leap. Stan Sieler of Allegro Consultants has started tests on the behavior of SSDs. But he has the 3000 and MPE/iX in mind. Sieler created DiskPerf for 3000 users, a powerful utility which must comprehend MPE storage rules to do its performance measurements.
"I'm thinking about SSD and SATA/SCSI adapters to speed up the 'obsolete- but still world's-best business computer, the HP 3000," Sieler said earlier this month. "I'm hoping to do some tests in the near future."
SSDs have a heritage in the PA-RISC generation of 3000s. Early in the 1990s, RAM-based drives were on offer for the community. They were far smaller than the drives of that era (much like the SSDs of today) and cost a king's ransom — which makes them differ from today's prices for such devices in the PC market.
Sieler says that the SATA/SCSI adapters are a crucial part of putting this tech advance on its feet. "Few SSD drives have SCSI interfaces... hence the SATA/SCSI adapter component," he says. "An SSD with a SCSI interface would look completely like an SCSI disk drive."
This kind of design, to mimic the SCSI interface, would permit Sieler to avoid using the SCSI Pass-Through code HP engineered during 2007 for the 3000. The community has heard no reports of how the pass-through works, and HP has said that employing it is "not for the feint of heart." Sieler's heart of MPE/iX experience is strong enough to include work for HP on some MPE/iX modules. But the engineer in him wants to count on his own coding.
The IT news source The Register has examined the prospects and hurdles in SSD use in its Channel blog. The latest Windows 7 is a minimum for the maximum benefit of SSD. "Windows 7 will use SSD speed much, much better than previous versions, and avoid exacerbating SSD problems by excessive random [write] operations," the article notes.
Sieler is among those in the 3000 tech community testing drives such as Intel's 160GB Mainstream units, priced at under $700. Even though there's lots of room for discounting such devices (components cost far less than moving parts), these drives have been popular, even in a down economy. Sieler reported on the speed leaps from his smaller test SSD.
The hard drive has a faster transfer rate (55 MB/sec near the outside, down to 32 MB/sec near the inside), vs. 20.9 (constant) for the SSD. This means that for random reads of less than one MB, the SSD is faster than the hard drive.
Defragmenting SSDs will result in a performance gain, for the same reason as on MPE: The mapping of file offset to disk address is quicker when you have fewer extents, assuming “ordinary” file systems (i.e., not a file system with direct indexing of page offset into an extent table).