12 Mar
2010
12 Mar
'10
3:47 a.m.
On Wednesday, March 10, 2010 at 9:28, dwight elvey wrote:
I don't have a 12821, it is a 59310. It should
work for most any HP-IB
thought.
One difference is that the 59310 is about 1/2 as fast: 470 KB/sec with
standard memory and 570 KB/sec with high-performance memory. The 12821 is
buffered, so DCPC can steal every I/O cycle vs. every other I/O cycle for
the 59310. Speed is 937 KB/sec. (Source: HP 1000/9000 Interface Products
Specification Guide, 5954-6312, August 1985.)
I suspect that if an unbuffered drive is used with the 59310, overrun
errors would occur. If they didn't, performance may be terrible, as you
might incur a one-rotation latency for each sector, unless the drive format
was interleaved.
The 12821 was the interface supported for hard drive connections under RTE;
the 59310 was positioned as an instrumentation controller.
-- Dave