Frequently when troubleshooting or cleaning PCs (ah, the joys of small business IT) it’s useful to have a bundle of tools that you can use. I generally use multiboot antivirus CDs created with Shardana Antivirus Rescue Disc Utility (SARDU) with additional utilities put in the Extras directory, but sometimes it’s hard to beat the convenience of a USB flash drive. Unfortunately very few flash drives still have the hardware write protect switch that was common years ago.
Here’s a listing of drives that still include that hardware write protection, along with some other options that might work though not as well. This listing is based on reports from several discussion boards in 2009-2010 as well as a list prepared and maintained by c’t Magazine (German) (or via Google Translate). Where available I provide links to the manufacturers and possibly to stores where the drives are available. Please comment with any corrections or additional drives to be added to the list.
USB Flash Drives with Hardware Write Protection
There are currently only seven models from four manufacturers readily available in the USA; I don’t have good data for what’s available outside the USA but will include any drives that I’m aware of regardless of US availability. Links to online suppliers are at the end of this article. There can be wide variations in speed between drives (e.g. USB Flash Drive Comparison – 21 Tested and Compared, which does not include any of the drives listed here but is informative), so check speed ratings and reviews where available. I mention some speed tests reported to USB Flash Drive Speed Tests below, if you have a flash drive feel free to check that website, test the drive and report the results.
There is a list with links to online stores that carry these drives at the end of this article. Drives not included in that list are ones that I didn’t find online sellers for. The stores used are Amazon, Newegg and the multi-store aggregator Google Products.
I have found very few of these drives in retail/physical stores. I’ve seen the Imation Clip in a few places that catered to students and the Imation Pivot and Swivel (both older model and newer) are carried in the CDW showroom near Chicago; beyond that I have not found the other drives locally available. The national computer (TigerDirect/CompUSA, Frys) and electronics (Best Buy) chains don’t list most of these drives as available online and for the most part don’t seem to carry many drives from these manufacturers at all (TigerDirect/CompUSA carries the Kanguru Defender Elites).
The Hama FlashPen “Fancy” (2GB, 4GB, 8GB, 16GB) appears to be primarily available in Europe. Only the 16GB gives speed figures, and its read speed of 6MB/sec seems low. According to c’t (link above) these are the same as the TrekStor USB-Stick CS described below.
Warning Note: Based on the experiences (April 2010) of the c’t editors, the pictures of the Hama drives are incorrect and only a small percentage have a write-protect switch.It’s not clear to me whether this also applies to the TrekStor drive; it’s possible that the early Hama drives were resold TrekStor drives and the later ones are manufactured separately.
Imation has two product lines with write protection switches, the Pivot (now discontinued) and the Clip. These should be widely available online and might be available in some stores. The Pivot appears to be the physically smallest of the available drives with write protection; the Clip is smaller and will fit tighter spaces but has a large protective carrier. The Pivot Plus does not list a hardware write protect switch on the website but does in the brochure; it also utilizes hardware-based encryption that may cause it to be incompatible with non-Windows systems.
Imation’s Swivel (not Swivel Pro) line used to have a write protect switch but it appears to have been removed on the current versions. The older versions have a gray/silver body, a dark swivel and a small LED on the side opposite the write-protect switch; the newer version without the write-protect switch has a black body, a black swivel and a LED in the center. Note that the Swivel Pro line resembles the older Swivel line but has a LED in the center and does not have a write-protect switch. Because of this change I do not recommend purchasing the Swivel online unless you’ve seen a picture of the actual product you’re getting.
Imation’s Defender line claims protection against malware in some models, but that appears to be based on requiring Windows or Mac encryption software to even access the drive. The user guide for the Defender F100/F150 does not mention hardware write protection, only the encryption software. The Defender F50 Pivot flash drive might have a hardware write protection switch – the Imation website shows a picture with one but does not mention it in the drive specifications; searches for the Defender F50 drive elsewhere turn up a variety of different images indicating that there may be multiple models available so I can’t recommend purchasing sight-unseen.
Imation does not provide read/write speed information on their website. Third-party testing of a 1GB Clip indicated a read speed of ~17MB/sec and a write speed of ~6MB/sec.
The Kanguru FlashBlu 2 includes a write-protect switch on the side. Capacity up to 128GB, read speed up to 20MB/sec and write speed up to 13MB/sec. The older FlashBlu drives (silver instead of blue) might have a switch based on the answer to a knowledgebase question, but there’s no other information about them online. Some vendors may still have the older drives.
Kanguru’s Defender Elite includes a write-protect switch and hardware encryption, but may not be compatible with all operating systems if encryption is used.It’s not clear whether it can be used without the encryption, but it’s expensive for a plain flash drive because you’re paying for the encryption hardware. The Defender Elite lists read speeds of 28-33MB/sec (20-33 for 32-64GB) and write speeds of 10-13MB/sec.
Update 2012-04-13: Only the base U339 model is still listed as available in this product line, and none of PQI’s other USB flash drives appear to have a write-protect switch. All of the other drives with switches are listed as discontinued by retailers and have disappeared from the PQI website.
Most of PQI’s U339 model line (including the U339,
U339XT, U339 Pro, U339H and U339S but NOT including the U339V) has a write protect switch in the endcap. I’ve seen cautions that the switch is somewhat fragile, and it may not be well-labeled but “With PQI logo facing upwards puch the switch to the right to prevent write / delete.”
PQI does not provide complete speed information on their website.
- The U339XT is listed as having a read speed up to 32MB/sec and a write speed up to 5MB/sec.
- The U339 Pro is listed as having a read speed up to 30MB/sec and a write speed up to 20MB/sec.
- The U339H is described as having “dual channel technology” and being “one of the fastest USB flash drives currently on the market” but does not provide actual speed information.
- The U339V (USB 3.0, 8-64GB) does not list a write-protect switch in its features, and no switch is visible in the photos they provide.
RiDATA EZDrive Slider (ID10) and Twister (ID15) models both have write protection switches. The Twister’s appears to be on the side of the drive; the Slider’s appears to be next to the slider button which means it’s protected when the slider is closed. Reviews of these are mixed, I’ve seen complaints about write speed so check the stats or reviews first if you’re going to be moving a lot data.
RITEK does not provide speed information on their website.
Trekstor (from c’t) – German manufacturer. USB-Stick CS product line features a write-protect switch (the same models can also be purchased in bulk with your logo printed on them as the USB-Stick yourLogo in quantities of 100+). Limited availability online. Website is multi-language and includes an interactive map showing countries with distributors. The TrekstorUSA (Thumbdrive) and Trek2000.com.sg websites do not appear to have been updated for 5-6 years.
Buffalo FireStix Type R (from c’t) – not listed on their website, but reportedly still available. Limited availability online. FireStix-branded RAM appears to be sold in Europe but not in the USA, but the European sites don’t list the flash drives. Flash drive part numbers for 2/4GB appear to be RUF2-R2G-S and RUF2-R4G-S.
I’ve seen mention of drives from Maxell with hardware write protection, but they do not list such drives on their USA website. If they are still available or are available internationally, please contact me with availability and part/model numbers. Ap.Tech is listed as having drives, but their website is nothing but a Flash intro.
Transcend sells industrial flash drives with write protect switches, these will likely need to be purchased directly from them. These drives do not have a standard USB plug, they are designed to connect to a 10-pin USB socket on a motherboard (take a look at the motherboard connector for front-panel USB ports on a regular PC for an example). Their product listing page is at http://www.transcendusa.com/Products/Modlist.asp?CatNo=122 for the USA, but they are also available from other international sites. Before purchasing read through the datasheet for the drives, available on Transcend’s website(s).
Victorinox SwissFlash (combination pocket knife & flash drive) drives are available but expensive. I’ll have more details up soon.
Opti3 / EasyDisk.com / EZDisk.com lists drives in capacities up to 4GB, but does not appear to have actually been updated since 2004. If you wish to place an order for a few 4GB drive for only $370/each, I’m sure they’ll manage to get drives of that capacity with write protect switches to you even if they have to buy Kanguru drives for $20/each from Amazon.
SD Cards – Not Recommended
SD Cards, while they have a write-protect switch, are actually no good for this purpose because it’s not actually hardware write protection – at best the card reader sends a signal to the operating system that the drive should be treated as read-only. The write-protect switch on the cards is read by a sensor that’s part of the card reader, and the card reader then passes along to the operating system whether the card is read-only. According to the specification from http://www.sdcard.org/:
A proper, matched, switch on the socket side will indicate to the host that the card is write-protected or not. It is the responsibility of the host to protect the card. The position of the write protect switch is unknown to the internal circuitry of the card.
Basically this means that either a) cheap card readers that lack the sensor or b) operating systems or malware that don’t respect the “please don’t write to this disk” flag can write to the drive. While this may not be likely, it’s also not as secure as you might think based on the presence of that switch.
Other Card Formats
There are some “Industrial” CompactFlash cards that include a hardware write protect switch, but they have limited availability. They are made by PQI and RITEK/RiDATA.
The earliest Sony MemorySticks had a hardware “Lock” switch, but it disappeared around the same time the capacity exceeded 128MB.
Software Tricks – Last Resort
There are a few software approaches that you can use in a pinch, but they’re mostly Windows-specific and it may be possible to bypass them – even if it seems unlikely.
Looking for a USB Flash Drive with Read Only or Write Protect Switch describes how to create a customized U3 partition based on an ISO file that will mount as a virtual CD-ROM. This will prevent items from being deleted from that virtual CD, but is not ideal for a system cleaning disk because the second partition can still be written to and infected. In addition, changing the contents of the protected area is a multi-step process that involves creating/updating an ISO file that is then used to re-create the U3 area on the flash drive.
USB Flash Drive Write Protection describes how the Windows Registry DWORD value WriteProtect in the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies key controls whether USB devices are writable or write-protected. A value of 0 (zero) allows writing to USB devices; a value of 1 blocks writing to USB devices. Changes may take effect after a logoff/logon, but will certainly take effect after a restart. There are several drawbacks to this approach: it might be possible for software to bypass it, it blocks writing to all USB devices, it doesn’t take effect immediately – it requires at least a logoff/logon and possibly a system restart and you have to undo your changes because it affects all USB devices not just your flash drive.
Several applications (shareware and free) and instruction sets simplify the process of write protecting by filling up the disk by simply creating temporary files to consume all available free space on the drive. If there’s no space to create even a small autorun.inf file, it’s difficult to infect the drive since it won’t run items by default when the drive is connected to a PC. This is probably better than nothing since it will stop some infections, but it may also give a false sense of security – it’s not complete security. One of the several sites with instructions for this is Raymond.CC’s Create Fake Dummy File on USB Flash Drive to Enable Write Protect and Prevent Modification.
I’ve seen instructions for protecting the files on a drive by reformatting to NTFS, then removing all permissions except a very limited set. Much like filling the drive to capacity, this may work against some malware but it’s not 100% protection. Setting this up also depends on the which version of Windows you’re running (assuming that’s what you’re using) – non-business versions may not provide access to the security settings needed, and non-Windows systems will likely either ignore the security or not be able to read the drive. This also makes it more important to tell Windows to eject the drive before removing it, because it’s more likely that Windows will be waiting before writing changes to the drive.
Here are links to these drives at major online stores or price-checking sites (Amazon, Newegg, Google Shopping). Google Shopping may get you the best price by a couple of dollars unless you’re getting free shipping from Amazon (or have Amazon Prime), but you may have to poke around a bit. If I didn’t list a store, they didn’t have any of the products when I created this listing, this includes TigerDirect and Fry’s Electronics. I was not able to find listings for the Trekstor or Buffalo products. This listing is US-targeted; internationally check with your regular purchasing options.
2010-03-15 added Kanguru drives, minor text tweaks. Added drive speed information where available.
2010-03-16 added notes about drive-filling and NTFS options
2010-03-18 minor note about older Kanguru drives
2010-03-29 updated with notes about in-store availability
2010-03-30 added Hama FlashPen Fancy, mention of Victorinox SwissFlash
2010-04-10 Noted link between Hama FlashPen Fancy and TrekStor USB-Stick CS
2010-05-04 Added Google Translate link to c’t FAQ, noted problem with Hama drives (from c’t)
2010-08-27 Added Imation Defender
2011-03-06 Removed Imation Pivot
2011-08-07 Added note about PQI U339V line not supporting write protect, removed note about Amazon affiliate program (no longer available in my state).
2011-08-19 Added Transcend industrial flash drives which use USB communications but connect to USB headers on a motherboard instead of to USB ports.
2012-01-11 Added Opti3 / EasyDisk / EZDisk for some level of completeness.
2012-04-13 Revised PQI to note that most of the drives listed here were now discontinued following a report and review of PQI’s site.
2012-04-14 Cleanup, revised link to Imation Clip, verified RITEK links/products, removed some dead/inappropriate store links.