CompTIA A_ Certification All-In-One Exam Guide, Seventh Edition - Michael Meyers [204]
The latest systems enable you to boot to a thumb drive. With a bootable thumb drive you can replace bootable floppies, CDs, and DVDs with fast flash drives. Making a thumb drive bootable is a bit of a challenge, so most of the classic bootable-utility CD makers have created USB versions that seek out your thumb drive and add an operating system with the utilities you wish to use. Most of these are simply versions of Linux-based live CDs. At this point there’s no single magic USB thumb drive to recommend, because bootable USB drives are still quite new, and updated versions come out almost daily. If you just have to try this new technology now, check out the GParted LiveUSB at http://gparted.sourceforge.net and click on the Live CD/USB/PXE link.
Flash Cards
Flash cards are the way people store data on small appliances. Every digital camera, virtually every PDA, and many cell phones come with slots for some type of memory card. Memory cards come in a number of incompatible formats, so let’s start by making sure you know the more common ones.
CompactFlash
CompactFlash (CF) is the oldest, most complex, and physically largest of all removable flash media cards (Figure 13-12). Roughly one inch wide, CF cards use a simplified PCMCIA bus (see Chapter 21, “Portable Computing,” for details) for interconnection. CF cards come in two sizes: CF I (3.3-mm thick) and CF II (5-mm thick). CF II cards are too thick to fit into CF I slots.
Figure 13-12 CF card
Clever manufacturers have repurposed the CF form factor to create the microdrive (Figure 13-13). Microdrives are true hard drives, using platters and read/write heads that fit into the tiny CF form factor. Microdrives are slower and use more power than flash drives and, when they were first introduced, cost much less than an equivalent CF flash card. From the user’s standpoint, CF flash cards and microdrives look and act exactly the same way, although the greater power consumption of microdrives makes them incompatible with some devices. These days, microdrives have been surpassed in size, speed, and cost by their flash cousins and have become more difficult to find.
Figure 13-13 Microdrive
SmartMedia
SmartMedia came out as a competitor to CF cards and for a few years was quite popular in digital cameras (Figure 13-14). The introduction of SD media reduced SmartMedia’s popularity, and no new devices use this media.
Figure 13-14 SmartMedia
Secure Digital
Secure Digital (SD) cards are arguably the most common flash media format today. About the size of a small postage stamp, you’ll see SD cards in just about any type of device that uses flash media. SD comes in two types: the original SD and SDIO. SD cards store only data. The more advanced SDIO (the “IO” denoting input/output rather than storage) cards also support devices such as GPSs and cameras. If you want to use an SDIO device, you must have an SDIO slot. There is no way to tell an SD slot from an SDIO slot, so read the technical specs for your device!
SD cards also come in three tiny forms called SD, Mini Secure Digital (MiniSD), and Micro Secure Digital (MicroSD) cards. They’re extremely popular in cellular phones that use flash memory, but see little use in other devices. Figure 13-15 shows the three forms of SD cards.
Figure 13-15 SD, MiniSD, and MicroSD cards
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NOTE SD cards developed out of an older, slower flash memory technology called MultiMediaCard (MMC). If you happen to have an MMC card lying around, you can use it in almost any SD card slot. SD cards are a little thicker than MMC cards, though, so the reverse is not true.
SD cards come in three storage capacities. Standard SD cards store from 4 MB to 4 GB, Secure Digital High Capacity (SDHC) cards store 4 GB to 32 GB, and Secure Digital Extended Capacity (SDXC) cards have a storage capacity of 32