5 ms·
There are only 3 forms of bit storage, historically. 1) Poking holes in things ( tape, DVD, etc ) 2) Magnets ( core memory, drum memory, tape, disks ) 3) Circu
by bbulkow 9y ago
There are only 3 forms of bit storage, historically.
1) Poking holes in things ( tape, DVD, etc )
2) Magnets ( core memory, drum memory, tape, disks )
3) Circuits ( DRAM, NAND, etc )
Examples of all three of these still exist.
What's interesting about XPoint is it is literally a fourth form that has never been commercially available: melting a substance and cooling it quickly or slowly, forming either a crystal or amorphic solid, which then has different properties. We don't know what the substance is, but it's cool that we now have this 4th thing.
- klodolph 9y agoThere are only 3 forms that really survive to this day. There are a couple of notable obsolete ones: 4) Delay lines. I would definitely not categorize these as circuits. The bits are stored as pressure waves in motion. 5) Electrostatic charge. Talking about the Williams tube. The bits are stored as residual charge on a phosphor surface.
- kabdib 9y ago... and magnetic bubble memory, which is a very odd hybrid somewhere between tape and delay lines. Also, phase-change optical (as in rewritable CDs/DVDs). Also also, printing stuff out at high bit-density with good ECC, and scanning it back in again. Also also also, chemically encoded bits (as in the DNA-based storage that was demonstrated recently). There are more, not in common use or very scalable (e.g., mechanical switches).
- klodolph 9y agoI think it's a bit conspicuous how you mention good ECC for printing stuff out, since good ECC is a staple of many forms of storage (especially hard drives, optical drives, tape) and we don't mention e.g. "storing bits on spinning rust with good ECC and reading it back in again". I think the problem with paper is thot it's not really part of the computer any more. You need a human to take the paper out of the printer, store it, and put it back in the scanner. At least with tape and optical, we have robots to do that for us.
- kabdib 9y agoI hadn't thought of that. Your average "crappy thumb drive" probably has more ECC than you'd need on a physical piece of paper. You're right.
- mtanski 9y agoAlthough when crappy thumb drives fail the whole thing tends to be unreadable or doesn't even show up as a USB device. Generally no amount of ECC will help the default failure mode of these.
- pinewurst 9y agoIs #5 that much different from dynamic RAM, with bits stored as capacitive charge?
- abtinf 9y ago> melting a substance and cooling it quickly or slowly, forming either a crystal or amorphic solid, which then has different properties This is exactly how rewritable optical media works.
- boznz 9y agoMemristors would technically be another form of storage but after the hype HP have been a bit quiet on this for the last 3 years.
- scurvy 9y agoMO drives heated the medium to the Curie point. 3D XPoint isn't all the revolutionary.