Comparison with other portable storage

Obsolete devices

Audio tape cassettes are no longer used for data storage. High-capacity floppy discs (e.g. Imation SuperDisk), and other forms of drives with removable magnetic media such as the Iomega Zip and Jaz drives are now obsolete and no longer an option.

Tape

The applications of current data tape cartridges hardly overlap those of flash drives: the drives and media are very expensive, have very high capacity, slower transfer speed than most other storage media, and store data sequentially, leading to very long access times. These devices are used for routine backup of large systems.

Floppy disk

Floppy disks are rarely fitted to modern computers and are obsolete for normal purposes, although internal and external drives can be fitted if required. Floppy discs may be the method of choice for transferring data to and from very old computers without USB or network support. Computers can usually boot from floppy discs, which can be a convenient way of updating flashable BIOS chips, etc.

Optical media

The various writable and rewritable forms of CD and DVD are portable storage media supported by the vast majority of computers as of 2008. CD-R, DVD-R, and DVD+R can be written to only once., RW varieties up to about 1,000 erase/write cycles, while modern NAND-based flash drives often last for 500,000 or more erase/write cycles.^{[citation needed]} DVD-RAM discs are the most suitable optical discs for data storage involving much rewriting.

Optical storage devices are among the cheapest methods of mass data storage after the hard drive. They are slower than their flash-based counterparts. Standard 12 cm optical discs are larger than flash drives and more subject to damage. Smaller optical media do exist, such as business card CD-Rs which have the same dimensions as a credit card, and the slightly less convenient but higher capacity 8 cm recordable CD/DVDs. The small discs are more expensive than the standard size, and do not work in all drives.

Universal Disk Format (UDF) version 1.50 and above has facilities to support rewritable discs like sparing tables and virtual allocation tables, spreading usage over the entire surface of a disc and maximising life, but many older operating systems do not support this format. Packet-writing utilities such as DirectCD and InCD are available but produce discs that are not universally readable (although based on the UDF standard). The Mount Rainier standard addresses this shortcoming in CD-RW media by running the older file systems on top of it and performing defect management for those standards, but it requires support from both the CD/DVD burner and the operating system. Many drives made today do not support Mount Rainier, and many older operating systems such as Windows XP and below, and Linux kernels older than 2.6.2, do not support it (later versions do). Essentially CDs/DVDs are a good way to record a great deal of information cheaply and have the advantage of being readable by most standalone players, but they are poor at making ongoing small changes to a large collection of information; flash drives' ability to do this is their major advantage.