You may need to replace a storage device when it no longer meets your customer’s needs or it fails. The signs that a storage device is failing might include:
- Unusual noises
- Unusual vibrations
- Error messages
- Corrupt data or applications
Floppy Disk Drive
While Floppy Disk Drives (FDDs) still have some limited uses, they have been largely superseded by USB flash drives, external hard drives, CDs, DVDs, and memory cards. If an existing FDD fails, replace it with one of the newer storage devices.
A hard drive stores data on magnetic platters. There are several different types and sizes of hard drives. Hard drives use different connection types. Figure 1 shows PATA, SATA, eSATA, and SCSI connectors. There are several factors to consider when purchasing a new hard drive:
- Adding or replacing
- Internal or external
- Case location
- System compatibility
- Heat generation
- Noise generation
- Power requirements
PATA hard drives use a 40-pin / 80-conductor cable or a 40-pin / 40-conductor cable. Choose the PATA hard drive if your customer’s system is a legacy system or does not support SATA.
SATA and eSATA hard drives use a 7-pin / 4-conductor cable. Although SATA and eSATA cables are similar, they are not interchangeable. SATA drives are internal. eSATA drives are external. Choose a SATA or eSATA hard drive if your customer needs a much higher data-transfer rate than PATA and the system supports SATA or eSATA.
SCSI hard drives use a 50-pin, 68-pin, or 80-pin connector. Up to 15 SCSI drives can be connected to a SCSI drive controller. A typical use for SCSI drives is to run a server or to implement RAID. SCSI devices are typically connected in a series, forming a chain that is commonly called a daisy chain, as shown in Figure 2. Figure 3 shows the different types of SCSIs.
Each device in the SCSI chain must have a unique ID for the computer to communicate with the right device. This includes the SCSI adapter. Typically, the SCSI adapter is given the highest number. For narrow SCSI, the IDs 0-7 are available. For wide SCSI, the IDs 0-15 are available. The controller is 7 or 15, and the other devices in the chain use the remaining IDs. In early SCSI installations, jumpers were used to assign SCSI IDs to adapters and devices. Modern adapters most often assign IDs using a program installed on the adapter or in the operating system.
Some drives may be capable of hot-swapping. Hot-swappable drives can be connected and disconnected to the computer without turning the computer off. Normally, to install an eSATA hard disk, you shut down the computer, connect the drive, and turn the computer back on. A hot-swappable eSATA drive can be plugged in to the computer at any time. External USB hard drives are also capable of hot-swapping. Check the documentation of your motherboard to determine if you can use hot-swappable drives.