New Way to Patch Defective Hardware

brunascle writes "Researchers have devised a new way to patch hardware. By treating a computer chip more like software than hardware, Josep Torrellas, a computer science professor from the University of Illinois at Urbana Champaign, believes we will be able to fix defective hardware by a applying a patch, similar to the way defective software is handled. His system, dubbed Phoenix, consists of a standard semiconductor device called a field programmable gate array (FPGA). Although generally slower than their application-specific integrated circuit counterparts, FPGAs have the advantage of being able to be modified post-production. Defects found on a Phoenix-enabled chip could be resolved by downloading a patch and applying it to the hardware. Torrellas believes this would give chips a shorter time to market, saying "If they know that they could fix the problems later on, they could beat the competition to market.""

Comments

Buggy hardware AND software?

[GoLGY]

"If they know that they could fix the problems later on, they could beat the competition to market."" Great, just what we need - hardware suppliers being encouraged to release buggy versions in the guise of fully working products.

Hasnt the lessons that have been learnt by the software industry had *any* impact?

bleh

[dave1g]

I was hoping for some idea like slapping an X gate FPGA onto the package of a regular processor, and then if in later testing it is deemed to have a bad cache line, or floating point unit. it could be reimplemented in the FPGA section and wired in, possibly increasing yields. Though these would certainly be lower quality parts they would atleast be functionally correct, if a bit slower.

But I dont know. Something tells me that if there is a hardware problem(not a hardware design problem) then it is likly that there will be others on the same chip, due too some non uniform distribution of impure silicon. and it wouldnt be long before there are too many corrections to fit in the fpga.

It's a new way to use FPGA technology

[mbessey]

The article IS light on details, but the last paragraph does explain how the system would work. Basically, manufacturers of mass-market chips would provide a small amount of FPGA-like programmable logic in every chip they make. This programmable logic would sit idle until some defect was discovered in the chip.

At that point, you can send a "patch" to the chip that uses the programmable logic to detect the error condition (or conditions that trigger the error), and work around the problem.

It's fairly clever, and is similar in spirit to the microcode patches that varios x86 CPU manufacturers use to correct for errors in their chips after they're taped out. It would be interesting to read about what the actual design is. It seems like coming up with a generic logic patching mechanism that can deal with previously-unknown errors would be a pretty interesting task.

Re:what?

[jd]

Both a dumb writeup and a dumb researcher. FPGAs are commonplace, patching them in-situ in the field is a little unusual but not particularly exceptional. They're cheaper to produce than ASICs (but much slower) but for a lot of stuff, performance is far more I/O-bound than compute-bound and so manufacturers can get away with using FPGAs. Plenty of companies never bother moving off of FPGAs at all.

Patches? Well, you think anyone on OpenCores is going to send patches via a soldering iron? No, they're going to reprogram the FPGA, the same as everyone else does. So even Open Source hardware has this guy beaten by many, many years.

Are FPGAs the only way to do this? Depends on what you mean. Processor-In-Memory devices pre-date FPGAs by at least a decade. PIM architectures are fun, as you get raw CPU performance without any memory access bottlenecks. Want to reprogram it? Well, it's just RAM. You can program it however you like! PIM is vastly superior to FPGA, if (and only if) you know the fundamental logic you are going to use and the fundamental logic isn't going to change. For example, you could build a PIM that had the whole of the MPI protocol built into it. Cray did exactly that. Your program on top of that will change FAR more often than the protocol itself, so so long as you code the protocol correctly in the first place, this will not only run faster but be far easier to change. No rewriting the VHDL or Verilog, because there isn't any.

But programming isn't the only time you'd want to patch defective hardware. Sometimes, hardware goes bad. You can't avoid it. A patch on an FPGA isn't necessarily going to fix that, because there's no way for the engineer to know what went bad and it wouldn't be cost-effective to re-engineer the code to put on it. Well, that's been thought of, too. Sir Clive Sinclair - possibly the most reviled figure in British computing - actually came up with a really neat solution. Simply make the system wafer-scale and format the compute elements as you would a disk. When something goes bad, mark the sector as bad. With massive redundancy and a near-zero failover time to a different sector, you could handle sizable chunks of the chip going up in smoke - something no FPGA patch would even remotely come close to.

Ok, what if you want something that looks and feels like an FPGA - then is this your only answer? No. SOGs (Seas of Gates) have been around for a while.

Finally, CPUs have long supported the notion of microcode - I believe one such system was hacked to run Pascal as the opcode not long after the language was first developed. Yes, that was some time ago. Hell, the Crusoe (if Transmeta had ever published how) could be programmed to look whatever you felt like making it look like. Talk about patchability!

The sheer number of solutions people have come up with to this problem probably outnumbers the gates on the FPGA the researcher was using. I can see nothing credible or interesting in this, and certainly nothing new.

Ultimately, of course, this has nothing to do with when someone invented whatever method. It has to do with when someone actually makes it ubiquitous. Alexander Graham Bell wasn't close to being the inventor of the telephone, but he marketed it like no-one else. That's what people react to and remember. Will this researcher turn what is frankly a pedestrian piece of work into a major slice of the market? I doubt it, but they might. If they do, then all the prior examples in the world will convince no-one. If they don't, then it's one more piece of research that's destined for the rubbish heap.