Feeds

Happy 40th birthday, Intel 4004!

The first of the bricks that built the IT world

Security for virtualized datacentres

You're either on the bus or you're off the bus

One major advance in the P6 architecture was the frontside bus. Before P6, interfaces between processors and the rest of the system were processor-specific. A true system bus, Pawlowski said, understands global addressability and not just processor I/O but system I/O, as well, and offers the opportunity to gang more than one processor and maintain cache coherency.

Intel 80486

Intel 486DX: 15MHz, 33MHz, or 50MHz; 1-micron and 0.8-micron processes (click to enlarge)

The P6's frontside bus used Gunning transceiver logic from Xerox, which was able to scale well and and continue to work as voltages declined. "We only thought it would last two generations, maybe two processor generations," Pawlowski said. Instead, it lasted for about a decade.

Another big step for the P6 architecture was out-of-order execution. "It had the reorder buffer," Pawlowski said. "It was able to look at more than three or four instructions at a time. Even if it could only decode and retire maybe three instructions at a time, it was able to have, potentially – gosh, if I remember right – I'm going to say 36 ... instructions that potentially could be in flight at any one time."

The P6's upgrades, he told us, helped that architecture achieve "performance improvements way above what we were getting with Pentium and the superscaler machine."

But perhaps the most radical – and radically effective – improvement in the P6 architecture, and one that helped out-of-order execution as well, was the translation of IA instructions into smaller, more granular micro-operations, or µops, which were more easily dispatched through the P6's out-of-order, superscalar architecture.

Intel Pentium

Intel Pentium: 60MHz or 66MHz, 0.8-micron process at introduction (click to enlarge)

As Pawlowski told us, "As I keep telling people today, 'We really do binary translation in hardware in these machines'." The beauty part of binary translation, he said, is that such binary translation to µops can work with different architectures while still keeping full IA compatibility.

"You've got the flexibility of changing the underlying machine," he said, and then rattled off some of those changes. "Every process generation and processor generation, we add better branch prediction, we may add different functional units like the trace cache that was added on Willamette [the first Pentium 4] ... larger vector units, adding a vector unit with AVX and then continuing to extend that, looking at ways to elide locks and make your locks faster but still maintain the semantics of locks because that's what programmers still use, but try to get the speed and limit the impact of contention so that we can just continually improve the processor performance."

All of those changes are more easily accomplished, Pawlowski said, in a processor that has full binary translation – and that's one of the things that the P6 brought to the party.

P6 lasted for three generations – the Pentium Pro, Pentium II, and Pentium III – but it was to make a comeback.

New hybrid storage solutions

Next page: Feeling the strain

More from The Register

next story
Apple iPhone 6: Missing sapphire glass screen FAIL explained
They just cannae do it in time, says analyst
Oh noes, fanbois! iPhone 6 Plus shipments 'DELAYED' in the UK
Is EMBIGGENED Apple mobile REALLY that popular?
Apple's big bang: iPhone 6, ANOTHER iPhone 6 Plus and WATCH OUT
Let's >sigh< see what Cupertino has been up to for the past year
Huawei ditches new Windows Phone mobe plans, blames poor sales
Giganto mobe firm slams door shut on Microsoft. OH DEAR
Phones 4u website DIES as wounded mobe retailer struggles to stay above water
Founder blames 'ruthless network partners' for implosion
Half a BILLION in the making: Bungie's Destiny reviewed
It feels very familiar - but it's still good
Apple's SNEAKY plan: COPY ANDROID. Hello iPhone 6, Watch
Sizes, prices and all – but not for the wrist-o-puter
DARPA-backed jetpack prototype built to make soldiers run faster
4 Minute Mile project hatched to speed up tired troops
prev story

Whitepapers

Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.
Top 5 reasons to deploy VMware with Tegile
Data demand and the rise of virtualization is challenging IT teams to deliver storage performance, scalability and capacity that can keep up, while maximizing efficiency.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.