2 ms·
DEC was always finnicky about naming; the PDP series originally wasn't supposed to be called a computer because computers were thought of as much bigger than th
by retrac 2y ago
DEC was always finnicky about naming; the PDP series originally wasn't supposed to be called a computer because computers were thought of as much bigger than the products DEC sold, and customers in the 50s and 60s might be put off by a name they associated with multi-million dollar expenses.
But the PDP-10 and VAX 9000 were basically mainframes. Million dollars or more. Whole large room with three phase power. Standard building AC might suffice but that was pushing the margin. And the faster clocked VAX 9000 was water cooled! That's not a minicomputer.
- mmooss 2y ago> But the PDP-10 and VAX 9000 were basically mainframes. Million dollars or more. Whole large room with three phase power. Standard building AC might suffice but that was pushing the margin. And the faster clocked VAX 9000 was water cooled! That's not a minicomputer. Why is that not a minicomputer. From our perspective it's a massive installation; from the perspective of the time, it was not necessarily.
- varjag 2y agoMinicomputer at the time was considered a system that fits in a rack or three. Not something that requires a purpose built room with own mains, raised floor and AC.
- deleted 2y ago[deleted]
- deleted 2y ago[deleted]
- somat 2y agoI am not exactly sure what makes a modern mainframe(same architecture as a historical mainframe I guess) but for historical machines I consider the wide machines(like the 36-bit pdp-10) mainframes, where minicomputers were usually narrower. 16 or 18 bit machines. Really there is no good formal definition, dividing computers into three groups(mainframe, minicomputer, microcomputer) based on how much you payed for it, is as good a mechanism for figuring this out as any other.
- brucehoult 2y agoMy PC is water cooled. However the VAX 9000 wasn't. It was initially designed to be water cooled but during development they improved the air cooling enough that water cooling was never shipped. One VAX 9000 CPU did around 70k Dhrystones/sec, so 40 VAX MIPS (DMIPS as we call them now). A modern simple RISC 5-stage in-order CPU (e.g. Berkeley RISC-V Rocket) with decent branch prediction does 1.6 DMIPS/MHz, so will need 25 MHz to match the VAX 9000. However the December 2016 HiFive1 ran at 320 MHz, so would be around a dozen times faster than the VAX 9000 -- but without FPU or MMU. Today, a $5 Milk-V Duo running at 1 GHz (64 bit, and with MMU and FPU and vector unit) will be 40x faster than a VAX 9000. The VAX 9000 has a vector unit, capable of a peak 125 MFLOPS. The Duo's C906 VFMACC.VV instruction has 4 cycles latency, for two 64-bit multiply-adds or four 32-bit multiply-adds, so at 1 GHz that's 1 GFLOP double precision or 2 GFLOP single precision, 8x a VAX 9000. Don't even ask what a modern i9 or Ryzen can do!
- karmakaze 2y agoI've used VAX and IBM systems and never heard anyone call a VAX a "mainframe". Looking into it, I get similar descriptions where they definitely were mainframe-class but refrained from calling them "mainframes" outright to distinguish them from IBMs. Other names Super VAX, VAXcluster/VMScluster etc were common. There probably were some that called their VAX computers "mainframe" but I'd never known of one--it just has the wrong connotations. The VAX systems were actually far more advanced in most ways--except for deployment scale.