Spindle motor
The spindle motor spins from the center to rotate the platter, at 3500 to 15,000 RPM. RPM is called revolution per minute. The number of weeks the spindle motor runs per minute… Currently, the most commonly used in our environment are 5400 RPM and 7200 RPM. This RPM must be taken into account when we buy a hard disk. The higher the RPM, the faster. One thing to keep in mind, though, is that the higher the RPM, the faster the data can be read, but the more power it provides.
SCSI drive
SCSI drives are commonly used on workstations and servers, rather than on ordinary computers. SCSI is a small computer system interface. There are two types of SCSI: internal SCSI and external SCSI. Let’s see the rate. SCSI 1 can only carry a 25-bit transfer rate using 25 pins. SCSI 2 is the same as SCSI 1 but with 50 pins instead of 25 pins. While SCSI 1 has nothing to speak about, SCSI 2 has a lot to say about SCSI VERSION. After SCSI 2, Wide SCSI has 68 pin and 16bit transfers. Fast wide SCSI can transfer up to 20 MBps with 16bit. Ultra SCSI can transfer 20 MBps with the 8-bit bus. SCSI 3 can transfer 16 bit and 40 MBps. It is also called Ultra-wide SCSI. So under SCSI 3, there are Ultra 2 SCSI and wide ultra 2 SCSI. Ultra 2 SCSI can transfer 8bit 40 MBps and wide ultra 2 SCSI can transfer 16bit 80 MBps.