FW: RK05 question

On Mon, Jul 12, 2004 at 08:34:22PM -0400, David V. Corbin wrote: I'd say it was because at the time, the predominant methods were either hard-sectoring (which is easy to key off of), or, for multiple platter drives, a servo *surface*. When you have only a single platter, filling the bottom surface with servo data kills your capacity. Also, keep in mind that the RK11-C, an early Unibus RK05 (RK03?) controller was made of several dozen "FLIP-CHIP" modules. Any design decisions that could keep that controller as small as possible would be a big win in terms of manufacturing cost. The RK8E was several quad-height boards (approx one square foot each). The RL01 came out a few years later with embedded among the sectors. This was a pretty good advance in drive technology. It's handy that the same packs were used with both the RL11 and RL8A controllers. At the time I first started getting into OMNIBUS PDP-8s (1984), I chose to go with an RL01 ($150 shipped) and an RL8A (~$600) rather than an RK8E ($450?) and adding another RK05 to the one I already had. Even in 1984, finding a 16-sector pack wasn't easy, but RL01Ks were available for nearly nothing (businesses were switching to RL02s) 5MB per drive (RL01) vs 2.5MB (RK05) was nice, too. -ethan -- Ethan Dicks, A-130-S Current South Pole Weather at 13-Jul-2004 01:30 Z South Pole Station PSC 468 Box 400 Temp -98.7 F (-72.5 C) Windchill -134.1 F (-92.3 C) APO AP 96598 Wind 6.8 kts Grid 103 Barometer 670.5 mb (10985. ft) Ethan.Dicks(a)amanda.spole.gov http://penguincentral.com/penguincentral.html