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MRAM Inches Towards Prime Time
levin writes "According to an article over at EETimes, magnetoresistive RAM chips are getting a little more practical. Infineon Technologies released info on a new 16M MRAM component on Tuesday and the read and write cycle times of this chip make it 'competitive with established DRAM.' How long before nonvolatile memory becomes the solution to crash-prone software rather than better programming?"
Once step closer to replacing HDD, CDROM, DVD and all those other "moving parts" storage devices.
In 20 years, we'll all be looking back at DVD and CDROM like we do at Tape Cassette.
Moving parts and things that go whirr make me cringe.
I just want to plug it in and get instant access.
The magnetoresistive cell can change the way ANY sequential logic circuit operates. It can make much denser CPUs, ASICs and FPGAs, because now you can make the clock input be THE power supply line.
... well, longer.
It can also make your timepiece battery last
You just need to look at it in a different view then Yet Another Non-PowerCycle-Erasable Storage.
Now one thing Novell is not is stupid. They refused.
Somehow, the story of the challenge got around the exhibition floor, and a crowd assembled. Perhaps it was gremlins. Never eager to pass up an opportunity, the keykos staff happily spent the next hour kicking their plug out of the wall. Each time, the system would come back within 30 seconds (15 of which were spent in the bios prom, which was embarassing, but not really key logic's fault). Each time key logic did this, more of the audience would give novell a dubious look.
Eventually, the novell folks couldn't take it anymore, and gritting their teeth they carefully turned the power off on their machine, hoping that nothing would go wrong. As you might expect, the machine successfully stopped running. Very reliable.
Having successfully stopped their machine, novell crossed their fingers and turned the machine back on. 40 minutes later, they were still checking their file systems. Not a single useful program had been started.
Figuring they probably had made their point, and not wanting to cause undeserved embarassment, the keykos folks stopped pulling the plug after five or six recoveries.
Want to improve your Karma? Instead of "Post Anonymously", try the "Post Humously" option.
And how exactly is one expected to code against this?
It's not difficult.
Just add ECC in software.
I've done this before in some of the software I've written for hospitals and banks; it's been a design requirement for the software to detect when there is a failure, and to correct if possible.
And, yes, failures ARE detected, AND corrected.
The way it works is you divide memory up into blocks (for example, 512 bytes of 1KB). You do this for both your data and code. For each memory block, store the ECC data (usually, in a separate area of memory, so it's non-intrusive to the program design).
A thread runs in the background, often on a second CPU, continuously checking the program's data and code to ensure that the ECC data is valid. When an error is detected, it is logged and corrected if possible.
When modifying data, a flag is set for that memory block that it has been altered; a new ECC value is calculated as soon thereafter as possible. (This is done automatically by setting the CPU to generate an exception when writing to a particular segment. It's a feature built into Intel processors and available through high-level calls in both Windows and Linux.)
I'm sure you remember the Java exploit from a couple of years back, where the security model was bypassed completely by blowing a hairdryer on the RAM until a byte code error was induced in very-carefully-constructed code. Software ECC is the kind of thing you need to do to mitigate those types of attacks.