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Comment by Animats | Hacker News Reader

The CDC 6600 was really a rather simple machine; it just had multiple copies of some units. The CRAY-I was even simpler, but had 64 copies of some units. Both were designed by small teams and had simple instruction sets.

The other extreme was the Pentium Pro, the first superscalar x86 CPU. I went to the talk at Stanford where the lead designer described the architecture. That was the most insanely complicated CPU built up to that time. People were thinking RISC was the future, because nobody could possibly get something as messy as x86 to go much faster by architectural means. But Intel brought it off.

One of the speaker's graphs showed the number of engineers involved over time. That peaked around 3000 people. Just getting that many people to work together to design one tightly-coordinated thing was an impressive achievement.

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> That peaked around 3000 people.

The number directly from the Pentium team was 3000.0000000001 people at the highest point.

The original Pentium was the first superscalar x86 CPU. Superscalar just means you can execute faster than scalar (one instruction at a time), and the P5 could theoretically sustain 2 IPC. Of course it was in-order so cache misses would likely prevent you from getting there.

The Pentium Pro was Intel's first out-of-order design. It's also superscalar.

StackOverflow has a really funny post by Andy Glew, who worked on the Pentium Pro, noting that a scalar out-of-order machine could make sense in some corner cases. (https://stackoverflow.com/questions/10074831/what-is-general...)

If you were an instruction pairing whiz, you could get pretty close to 2 IPC on the Pentium I for certain kernels.

The thing that Seymour had going for him at CDC is that he didn't bother with synchronous exceptions. On x86 (I worked on a late 486, Pentium I, Pentium II and Itanium II) you absolutely must have synchronous exceptions for backward compatibility. Debugging an exception on 6600 was a hair-tearing exercise, because the PC point somewhere near, not at, the instruction that raised, and there may be a swiss-cheese window of instructions that did not complete somewhere before that. Loads of fun for one and all. (I used 6600/7600's while working on Cyber 203/205 at CDC).

I think that’s not quite correct re: the Cray 1 having 64 copies of certain units. True, the vector registers did have 64 entries but the vector functional units were pipelined. They could return a result each cycle (once past the initial latency) but did not return 64 results simultaneously.

> The CDC 6600 was really a rather simple machine; ... The CRAY-I was even simpler

Pretty bold claim, can you explain why you believe this is so?

> But Intel brought it off.

Not by buying up and killing the Alpha AXP, oh no.

The DEC Alpha was the swan song of Digital Equipment Corporation, which was bought by Compaq (a PC manufacturer that peaked in the 1990s), which was bought by HP.

Intel had little to do with it.

I don't know the details, but from Wikipedia: "In May 1997, DEC sued Intel for allegedly infringing on its Alpha patents in designing the original Pentium, Pentium Pro, and Pentium II chips. As part of a settlement, much of DEC's chip design and fabrication business was sold to Intel."

In the 1990s, especially latter half, Digital's leadership went on divestment-oriented business management, and managed to ultimately divest the company of its future.

In hindsight, weren't they basically finished by 1989?

We'd be living in a different world if they'd put all the money from the VAX 9000 into RISC CPUs instead.

there was a whole line of mips decstations. I think that part of the market was already saturated for them.

Not really - Alpha was quite successful. My personal suspicion is that if instead of chasing quick returns through divestment that had worked on keeping a portfolio of products that drove sales for each other (for example, Rdb which to my understanding was fairly successful in some areas) the results might have been different.

There's reason why so many places kept to Digital gear even after Compaq mishandling, then the Itanium and HP days, and not all of those were customers that had problematic rewrites blocking any migration (like customers dependant on VMS).

I am still not sure what the killer app was for the Alpha. Other than OpenVMS/Alpha to provide the business continuity for existing VMS customers, DEC was not really all that successful with the Alpha from that perspective.

Yes, Windows NT Alpha did take off initially and was the go-to non-Intel platform for CPU hungry apps, but it was expensive and then Intel caught up with multi-processor Pentium Pro systems and that was the end of the Alpha.

Sun SPARC/UltraSPARC was effectively a hardware appliance to run the Oracle database (and SAP). SGI/MIPS covered the 3D graphics market. IBM POWER was the hardware to run DB2 and other IBM wares ported from mainframes for customers who did not want to have to deal with JCL and other hairy stuff. HP PA-RISC was an enigma that ran something although not that many people were sure what exactly it was. HP Superdome was pretty rad tho – I worked on a project for a telco that had purchased a 128 CPU Superdome to run their billing system on (ironically, it was IBM who had sold them on the Superdome). HP-UX before v11.21 had been buggy AF and overall an abomination.

Yes, Alpha could run Oracle as well, plus other things… they never seem to have taken off tho, and Alpha was quickly relegated to an IP garage sale.

From the technology perspective, Alpha was a resounding success, at least in the beginning.

The hardware appliance for Oracle was Itanium on HP-UX. Oracle pushing it as recommended platform until their Sun acquisition is pretty much what kept it afloat after introduction - if the billing system used Oracle RAC as backend, it might be the reason for using Superdome.

From my perspective, Alpha had quite wide user base, not as much as Sun which seemed to have figured desktop unix sales way better than everyone else. I know some segments tended to buy Digital because if you knew what you wanted, Digital would let you simply order it - disappearance of that approach, forcing everyone to go through a sales rep, has been anecdotally pointed to me as why a bunch of places migrated post Compaq acquisition.

> hI am still not sure what the killer app was for the Alpha

It was a general purpose processor, talking about a single killer app doesn't make sense. It was designed for speed and expandability and as such seemed very successful.

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