Comment Re:Flash drives (Score 1) 669
The point is that the thermal filter cannot adjust for cosmic radiation because the cosmic ray hit is far above the thermal noise level.
The point is that the thermal filter cannot adjust for cosmic radiation because the cosmic ray hit is far above the thermal noise level.
True, thermal noise is uniform over the detector (N=aT), N= noise level, a=Temperature dependent noise coefficient, T exposure time. Cosmic particle hits act like stuck pixels
noise generated in the camera is a statistical fluctuation (0-aT) T exposure time, a is temperature dependent noise coefficient, cosmic particle hits act like a stuck pixel. Cosmic rays definitely do not streak in digital devices. They most commonly dissipate their energy in one cell only.
Not in favour of SSD drives for long term storage. I use RAIDz2 too in my setup. FreeBSD/OpenSolaris/Solaris/MacOS X, all doesn't matter to me, as long as it is ZFS (or something comparable).
The SSD drives are not immune to data corruption in the long term (older technologies actually fare better than newer high density SSDs), unless you 'respin' them once in a while.
I'm married...
nuf said.
I hear you, my biggest worry isn't fire itself, its fire after earthquake. In addition to my backup solution described above, I keep rotated drives with snapshots at work.
If my house burns down completely and all data is unretrievable I will have lost at most 6 months of data. Not all.
Even quality DVD surfaces (on DVDs you can burn yourself) degrade quickly over a period of time (in my experience 2-4 years). Doing a re-backup every 3 years is too risky, it would have to be every two. In my case, with close to 1.6 TB of personal data (video, pictures, the works) it is not even practical, it would mean doing a re-backup of a DVD every two-three days.
Actually Flash/memory drives are sensitive to radiation. Long term storage without regularly accessing the drive can lead to situations where blocks go bad beyond the ECC/CRC capabilities of the drive to fix. If you intend to store valuable data on memory devices for the long term you should (a) use multiple redundant drives (b) use a file-system with block-level ECC/CRC error correction and redundancy (like ZFS) (c) write each block to the device twice in different location (i.e. an mirror on the drive).
The future of Flash memory is such that unless they extend the ECC/CRC capabilities of the controller, the susceptibility of these devices for radiation will increase when the cells get smaller.
In case anybody doubts the impact of radiation on electronic devices, here is an interesting experiment you can do: take your digital camera, put the lens cap on and do timed exposure with increasing exposure times (1,2,4,8,
To cut my somewhat rambling post short: use memory devices as long term storage? No. Not without thought about the required data reliability.
I recently built my own cheap backup server using OpenSolaris and ZFS. I used my old SATA drives (6x400GB), a $75 motherboard and AMD Athlon X2 combo, 4GB of DRAM ($69) and an old tower case. I did add two SATA 5-bay hot-swappable disk bays ($110 each) so that I can easily replace/upgrade my disks. Once a week I update data from my main server (also Solaris) to the backup server using ZFS incremental snapshots.
My PC's and Mac's all mount their user directory from my main server, and I rsync my laptop every day. The main server also serves as a SunRay server so I do most of my daily chores on a SunRay. I run Windows inside VirtualBox and I rarely ever turn on my windows PC anymore (the Windows instance in VBox also mounts from my main server). Inside my main server I have 2x 1TB drives, in a ZFS mirror setup, for the user directories and 2x400GB for the OS and scratch directories (all drives are SATA).
I'm very confident in this setup, also because I can yank out my drives in under 30 seconds in case of fire. The only thing I still have to do is put my backup server in a different room from the main server - that is a todo project for the near future.
A RPG can inflict serious damage to the superstructure of modern warships - they simply where not designed for close-in tasks like stopping and searching pirate vessels. The risks of asymmetrical warfare are such that a $100 piece of pirate weaponry can inflict $1000s of damage. More robust warships (less electronic gadgetry, less things to damage) would shrug of the damage from these lighter weapon types without having to immediately resort to lethal force.
Not according to the Intel X25-E specs...
Care to provide some proof? I don't believe for a second that an SSD drive can intelligently copy bits from a hard-drive. It would violate the way storage drivers work. The system does this, not the drive.
You should use a mix of SLC and MLC. MLC for the frequent read, infrequent write, SLC for the frequent write.
There is more underneath the covers than meets the eye.
Real magic would have been demonstrating a move between ANY processor architecture - Power, SPARC, x86_64 etc..
Between x86 processors is nice, but not unexpected.
A penny saved is a penny to squander. -- Ambrose Bierce