[Ham-Computers] RE: Flash Drive Selection

Mon Mar 3 14:40:42 EST 2008

OK, so it sounds like there are 3 or 4 questions to be answered...

What brand drive should I get?
Well, I'd stick with "major" flash memory vendors such as Sandisk and Lexar.  I have several Lexar "Jump" drives and also have a couple Corsair Voyager drives.  Try to find a brand with the longest warranty - it won't help with data recovery if it fails, but at least you'll get a replacement unit.

Speed
Speed is highly dependent on the type of flash memory chips(s) and controller are used in the flash drive itself.  Single-Level Cell (SLC) flash memory chips are the faster, but cost more to manufacture than Multi-Level Cell (MLC) flash chips.  Most of the "high-speed" flash drives use SLC memory.  SLC flash is lower density than MLC, so you'll also notice that the higher speed drives are only currently available upto 4GB.  Right now, 1GB and 2GB flash drives are typically faster than 4GB or larger flash drives.  I've read that Micron just produced an 8Gbit SLC flash chip, so 8GB SLC drives might be available soon.  Realize that 8 of these chips are required for an 8GByte flash drive and you'll understand how size plays a factor compared to speed.

The controller also plays a factor due to the block-level access of flash drives.  Depending on the block size, write speeds will vary.  Flash drives generaly have the hardest time with writing many small files.  Also, due to the limited number of write-cycles of flash cells, the controllers use "wear-leveling" and always use a different address when writing data - this, combined with the block-level access is what causes slow writes.

So, how to determine what drive to get based on speed?
Try looking for a drive that is Microsoft "ReadyBoost Ready".  ReadyBoost is a caching method developed for Windows Vista that requires that the flash drive meet certain *random* read and write specs.  Generally, if a drive is ReadyBoost ready, it has good random-write speeds.  Don't be fooled by a "Vista Ready" logo - all flash drives can be used with Vista.  Only drives with the "ReadyBoost" logo have passed the ReadyBoost specs.  However, Jim, since you're looking for 8GB drives, you probably won't find any that are ReadyBoost ready as most 8GB drives are MLC.  In this case, look for guaranteed write speed labeling.  However, take these with a grain of salt as the speeds are often for sequential writes, not random.

NTFS vs FAT32
General recommendation is to only use NTFS on non-removable drives.  The reason is that NTFS volumes are always "open" when mounted and metadata could be lost if the drive is disconnected.  NTFS is a "journaling" file system.  It *seems* faster as it writes *everything* to a journal file prior to actually writing the data to it's proper place on the drive.  So, in essence, it's writing the data twice.  It writes the original request to the journal file (as metadata), and, when the OS is less busy, it moves the data from the journal to a proper location on drive.  Should the drive be removed during this operation, data could be lost or corrupted.

FAT32, on the other hand, does everything immediately, but at the cost of holding up the OS while it's doing it's thing (no caching).  Much safer as the only time data can be lost (vs NTFS) is if the drive is pulled while a write is occuring - less likely to happen if you're actively saving a file and waiting for the save to finish.

Whichever you decide on, the safest way to remove any removable drive is to eject it or use the "Safely remove hardware" icon.  If Windows has anything open and can't remove the device, it will tell you so.  Honestly, I rarely use either function...but I *know* what to look for when removing the device.  I know it's not failsafe, but I've been lucky so far!

73,

  - Aaron, NN6O

-----Original Message-----
Sent: Monday, March 03, 2008 10:47 AM
Subject: [Ham-Computers] Flash Drive Selection

I'm looking for two 8 GB flash drives and would appreciate any 
opinions.  Reliability is very important, and speed nice, as  I'll 
use them to save emails.  I currently have two 4 GB drives which are 
used alternately every few days, so if I have a failure I still have 
fairly recent data available. I have had no problems with them, but 
they are almost full.  I attempt to touch metal first when inserting 
the drive, and use the Safely Remove Hardware feature on the system 
tray before removing the drive.

I'm running XP Pro with current updates.

I've purchased 10 flash drives over many years, and have had perfect 
reliability from 9.  The 10th, a  4 GB PNY Attache, failed while 
consolidating my documents, a really inconvenient time.  Actually, it 
was a partial failure that seemed to affect recent documents while 
others not accessed for a long time seemed to be ok.  I've used many 
Word repair programs and have been fairly successful, except for 
table structure (words remain, without the table).  I don't know if 
the problem was really a drive problem or cockpit error.

Pricing seems to be really variable between drive manufacturers, and 
different retailers for the same manufacturer.  So far, I've checked 
Newegg and Amazon.com.  Both have good pricing and also ratings from 
purchasers.

Newegg lists a Tanscend JetFlash V10.....Model TS8GJFV10.  Going 
through the 3-ball comments 
http://www.newegg.com/Product/ProductReview.aspx?Item=N82E16820208094&SortField=0&SummaryType=0&Pagesize=10&SelectedRating=4&PurchaseMark=&VideoOnlyMark=False&Page=
Author "NTFS", who rates his tech ability as "high", says

Pros: Large capacity.

Cons: As other stated - very slow for small files. It sucked.

Other Thoughts: While the Windows Disk Management tool will only 
allow a FAT32 format you can format this drive NTFS from the command 
prompt, (where the real power is). It may take 4-5 minutes to create 
the file structure but it will make small file transfers very fast. I 
am running XP pro, SP2. (Use at your own risk - volume "E" was the 
8GB flash drive): C:\WINNT\system32>format E: /FS:NTFS Insert new 
disk for drive E: and press ENTER when ready... The type of the file 
system is FAT32. The new file system is NTFS. Verifying 7871M Volume 
label (ENTER for none)? USB Drive Creating file system structures. 
Format complete. 8060892 KB total disk space. 8018068 KB are 
available. C:\WINNT\system32>
.................................................................................................................................................................................

Any comments on his suggestion?  I've heard FAT32 should be used on 
external hard drives, but don't know why.

Thanks, Jim

______________________________________________________________
Ham-Computers mailing list
Home: http://mailman.qth.net/mailman/listinfo/ham-computers
Help: http://mailman.qth.net/mmfaq.html
Post: mailto:Ham-Computers at mailman.qth.net