Hard Disk: Know What You’ll Use It for

What do you look for when buying a hard drive? We’ve classified these under three heads: Storage space and price, factors effecting performance, and the interface used.

First, what do you need it for? Will you put the disk on a PC that will be used for normal applications? On a server that is expected to handle heavy client loading? On a CAD/CAM workstation? Or on a machine handling live video?

Depending on the use, you have to choose the right technology and capacity. For example, a 20 GB IDE disk is good enough for a normal desktop machine, while the best choice for a server may be a 50 GB SCSI disk and that for a live video workstation would be a 60 GB Firewire external hard

disk.

Interface



Disk drives are available in two popular interfaces: IDE (Integrated Device Electronics) and SCSI (Small Computer System Interface). An interface is the channel over which data flows to and from the hard disk. IDE is the most popular and commonly used interface in disk drives today. The current standard in IDE is UltraATA/133 and hard drives with UltraATA/133 interface have also started shipping. SCSI drives (pronounced scuzzy), on the other hand, are much faster than IDE drives and are commonly used in high-end appliances, such as servers. They are also much more expensive than IDE drives. An 18 GB Ultra 160 SCSI drive, for example, costs around Rs 16,720.

Storage space and price



The size of your hard drive depends on the kind of applications you are going to run on it. For normal productivity applications, such as Word, Excel, e-mail or Internet, a 20 GB hard drive is more than enough. A 20 GB drive costs some Rs 4,000 to Rs 5,000, a 40 GB drive Rs 6,000, an 80 GB Rs 9,000 and a 100 GB around Rs 13,000. Hard drives today can store up to 160 GB of data. The latest hard drive from Maxtor can store 160 GB of data and is priced at Rs 20,000. You may want to partition larger hard disks into more manageable volumes.

Performance



Once you’ve decided on the technology and the space you need, the next thing to look for is performance. Various things, such as seek time, transfer rate, cache and spindle speed, affect the performance of a drive.

Seek time is the time required for the read/write heads to move between tracks. The lower the seek time, the better the performance of your drive. Data transfer rates are measured in MB/Sec, and the higher the transfer rate the faster the performance of your HDD. When it comes to cache, needless to say, the larger the better, as it can store more data, and data can be picked up quickly from the cache rather than the HDD every time. Cache refers to the memory area of the HDD, which stores recently accessed data of your hard drive. So, look for fast data transfer rates, a low seek time and a larger cache.

Next comes the spindle speed or the rpm of the drive. This is the speed at which the platters rotate. The higher the spindle speed the faster your hard drive. 5,400 rpm and 7,200 are the two commonly used rpms for IDE disk drives. For normal productivity applications a 5,400 rpm drive is good enough. In SCSI you go up to 10,000 RPM.