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Alpha's Going Going Gone
WildCode writes "Get your Alphas now cause HP is releasing the last of the Alphas (the final one expected to be released in 2004), and there will be no more." I was already under the mistaken impression that Alpha was dead, so this story is rather bittersweet for me. Still, as far as architectures go, Alpha will probably be among my favorites. It was once vastly ahead of its time, if not severely cost-prohibitive.
Hewlett-Packard plans on Monday to begin selling the last and most powerful model in the AlphaServer line, a series of servers that stretches back to a very different era in the computing industry.
The 64-processor AlphaServer uses EV7 processors, the company said Friday. Previously, the top-end system was the 32-processor GS1280, released in July.
The 64-processor model will be the last in the AlphaServer line, an HP representative said. However, HP plans to update it with a faster processor in 2004, the EV79, which the company said would be the final processor in the Alpha family.
The AlphaServer line began at Digital Equipment and outlasted that company's 1998 acquisition by Compaq Computer. Compaq, though, decided to phase out the Alpha processor, adopting instead Intel's Itanium processor family.
Alpha was respected for its speed, but the chip never caught on widely, despite temporary support from powerful allies, including Microsoft. It competed with chips from HP, Sun Microsystems, IBM and Intel.
HP took over the AlphaServer line when it acquired Compaq in 2002.
One major feature of the AlphaServer line will live on: the OpenVMS operating system. That software, born more than 25 years ago as VMS (Virtual Memory System), is being moved to the Itanium processor.
Another operating system that runs on Alpha, the Tru64 version of Unix that also came from Digital Equipment, is being phased out in favor of HP-UX. HP engineers are working to bring some features of Tru64 to HP-UX, however.
HP plans to announce improvements to Tru64 and OpenVMS on Monday. The company will also release a new entry-level AlphaServer that uses the EV7 processor, the company said.
Indeed, Alpha, unlike all the other 64bit processors mentioned, was designed from the ground up as a 64bit cpu, rather than a 32bit cpu with 64bit extensions added in. Itanic was supposed to be designed like this too, but they screwed it up somewhat.. All the other 64bit architectures have to retain some compatibility with older 32bit architectures. Alpha maintained compatibility via software emulation, and did so very well simply because of the huge performance difference between the last of the VAX and the first Alpha chips, the early alphas could also emulate x86 hardware faster than real; x86 chips of the time.
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I have liked alphas since I first laid hands on one back in 1993 when it was running OSF.
I have a few of them kicking around my house, a couple of EV6s and an EV4 that still does sterling service.
Alphas were always fast, both integer and floating point, however it was the FP performance that really made them popular for scientific applications. Once the EV6s arrived the integer performance increased considerably over the previous EV5s with the addition of four integer pipelines (EV5s had two each for integer and FP) and also register renaming and instruction reordering. Alphas have 32 64 bit integer registers and 32 floating point registers, but an additional 32 showed up in the EV6 which allows the processor to do a lot more work per clock cycle along with the extra pipelines and out of order execution. The other great thing that EV6 introduced (well, actually the 21164PC chip introduced it but it wasn't as useful as the 264 EV6) was MVI. This is the equivalent of the Intel SSE/MMX instructions but the MVI instructions had direct access to memory as they were 64 bits wide just like any other instruction on the chip. This meant it was trivial to load up a 64 bit word and then do parallel work on the data such as sum or max.
Instructions also executed very quickly, typical of a RISC chip, and the processors had very large caches for their day (2MB being typical but server chips had much more than that). Even access to main memory was very quick, the EV6 bus was also used on the Athlon for this reason.
So, you essentially had in Alpha a processor that has able to crunch integer and FP data very quickly, had a fat bus to memory with a cache large enough to be useful and lots of general purpose registers, extended parallel instructions that worked easily with the existing instruction set, one which looks like an high level language it is that easy to use. They also had very high clock speeds for their day and used those cycles very efficiently, Alphas were running over 500Mhz when Intel was putting out sub 200Mhz 32 bit chips that struggled to do more than a no-op in the time that an Alpha could do a fourier transform!
Unlike Itanic, the Alpha was designed to make compilers easy to write, Compaq released the DEC compiler to work under Linux and it was amazing to see the boost in speed that came about when that was used. The fact that the EV6 was so smart meant that the compiler didn't need to be all that clever to make code that Alpha could run very quickly. It was pretty simple to avoid cache misses and other performance sapping problems.
Compared with other processors of their day such as SPARC the Alpha was at least twice as quick if not more. It is only as Compaq took over and took their foot of the pedal and speed ramps dried up that other architectures caught up but it took some time. If they had continued to keep pace with die shrinks and clock speed increases Alpha would have been embarrassing its competitors even today, in fact it still is if you witness the fact that HP won't release benchmarks for EV7 until Itanium can beat it.
So, yes, Alpha was great and I haven't even touched upon EV7 as I never got my hands on one and I'm not likely to now. Damn HP. Damn them to hell!
From what I have heard it is quite likely that Alpha EV8 technology will live on as the next gen Itanium, effectively something like the current Pentium where the Itanium instruction set will be wrapped around and Alpha style core with translation to make it seem like an Itanium. Yuk.
As I said, Damn HP.
"I have the attention span of a strobe lit goldfish, please get to the point quickly!"
" Too bad itamium isnt a miserable failure, but the fastest CPU on the planet"
I think you'll find Cray Research taking issue with that , not to mention a number of military DSP producers. I think what you mean is "fastest
consumer/business mass production CPU"
"Dont bitch that they run hot and are huge. Name any alpha that wasnt >300 mm^2 and a power-sucker"
That was over 10 years ago. This is 2003 , not 1993. Why are intel re-inventing a broken wheel? Why don't they use the expertise they have in their
alpha engineers and produce a CPU that doesn't roast itself from day 1? Or have they all parachuted in from a time warp?
That's what we called them when I worked at DIGITAL (up until Compaq canned a lot of people right after the purchase and almost killed the Alpha then).
They are still ahead of their time. The fastest Alpha's (EV8, over 1GHz) were still far faster than an equivalent speed x86 processor.
I've heard repeatedly that Samsung will still be producing the processors. I have not looked into this recently though.
It's a shame to lose such a great architecture. Yet another example of the best ideas not always being the most popular or surviving. At least part of the architecture will live on in AMD chips (for now at least).
PGA
The fact that the EV6 was so smart meant that the compiler didn't need to be all that clever to make code that Alpha could run very quickly.
I guess "smart" is a relative term I guess how you apply it. If you say the designers were smart in making the chip very simple (dumb) which made compilers easy to write because there weren't that many ways to do a particular thing well, then I'd agree with this statement.
The thing about the Alphas were they really were RISC. The 21064 has *horrible* performance with strings and byte oriented operations because byte level addressing was not present in the instruction set. String manipulation and the like were synthesized in the libraries by using shifts, masks, and such. Not a very *smart* CPU... quite dumb actually (not that this is a bad thing... it made it simple). The story was that the designers were a little too purist with the first Alpha and "underestimated" the amount of byte level operation/addressing that was used or something or just wanted to really make the Alpha a number cruncher. At this level of the architecture, there was no out of order execution or the like. A pipeline stall caused *everything* to stop until the memory request was handled.
Very shortly after the 21064, byte level addressing and manipulation was put into the Alpha line. Of course, this was really nice and improved a lot of those type operations. Also, out of order execution was put in at a later point. That was the really nice Alpha.
As far as living on... there are many CPUs today that have at least a part of their lineage with the Alpha. Either their FSB (Athlon), their philosphy (high clock speeds), or direct decendents (StrongARM).
Another bit of history: at the time the Alpha was released, HP had another CPU that they liked a lot. It was the PA8000 family. The PA followed the "wide" philosophy of processor speed - it had lots of execution units, out of order execution, and all the other stuff that we see a lot of today. The problem was that all of that extra circuitry made it *extremely* difficult to ramp up the clock speed. People referred to this camp of design as the "Brainiacs" because they did a lot per clock cycle and the clock speed was fairly low because of the complexity of the chip. The Alpha camp was called the "Speed freaks" in that they believed high clock speed was first, then later design in the complexity. Anyway, the PA8000 and the Alpha started out about the same speed but HP just couldn't keep up with the clock speed ramp up of the Alpha.
So... I guess back to the original topic... the Alpha was easy to write compilers for early on because of the simplicity of the instruction set (the chip is "dumb"). Later, when the Alpha crew added the byte operations/addressing it simplified some library writing. Later, out of order execution and such were added which didn't really impact the complexity of the instruction set as much as just made the compiler better. The OOE is where the "smarts" came in.
Too bad itamium isnt a miserable failure, but the fastest CPU on the planet.
Of course it is, if you believe HP has declared that "...no Alpha benchmark will be released until the Itanium platform(s) is/are faster."
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Dum de dum.
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