On Mon, May 19, 2025 at 9:43 AM Noel Chiappa <jnc(a)mercury.lcs.mit.edu> wrote: Indeed. Extinction of existing practice by new technology happens all the time and not just in the computer field. Before sound recording and playback was invented, fancy restaurants, hotels, etc. hired orchestras to play background music. The phonograph put a huge number of orchestras out of business. There's a knee-jerk tendency in our industry for companies to respond to new technology by retreating to the high end of the market in an attempt to protect profit margins. IBM did this when minicomputers came along; Apollo did it when confronted with cheap workstations (Sun); DEC did it when the PC appeared; Intel right now is attempting to do it to stave off competition from ARM. In all cases the effort has been unsuccessful and usually has resulted in the death of the company (IBM has survived, but as a shadow of its former self). I think it was Scott McNealy who said (regarding protecting existing products and profit margins) that a tech company must be prepared to eat its own children. If they don't, the competition will. -Paul W.

On Mon, May 19, 2025 at 12:36 PM Noel Chiappa jnc(a)mercury.lcs.mit.edu wrote: The CPU ISAs may be largely shared, but computing has bifurcated into two distinct camps: those machines intended for use in datacenters, and those intended for consumer use by end-users. CPUs intended for datacenters tend to be characterized by large caches, lower average clock speeds, wider IO and memory bandwidth. Those intended for consumer use tend to have high clock speeds, a bit less cache, and support for comparatively fewer IO devices/less memory. On the end-user side, you've got a further split between laptops/desktop machines and devices like phones, tablets, and so on. In both cases, the dominant IO buses used are PCIe and its variants (e.g., on the data center side you've got CXL), NVMe for storage is common in lots of places, everything supports Ethernet more or less (even WiFi uses the ethernet frame format), and so on. USB seems ubiquitous for peripherals on the end-user side. In short, these machines may be called "personal computers" and they may be PCs in the sense of being used primarily by one user, but contemporary data center machines have more in common with mainframes and high-end servers than the original PCs, and consumer machines are much closer architecturally to high end workstations than to yesteryear's PCs. My desktop machine is a Mac Studio with an ARM CPU; I call it a workstation and I think that's pretty accurate. At work, one of our EE's has a big x86 thing with some stupidly powerful graphics card that he uses to do board layout. It's a workstation in every recognizable sense, though it does happen to run Windows. - Dan C.

Interestingly, some of the earlier Sun machines were VME based. As I recall, if you popped the hood off of a "pizzabox" Sun 3/50, there was a VME SBC in there with some drive bays. In that regard, the SPARCstation 1 paper is worth reading as an evolutionary marker. - Dan C.