1956
IBM invents the first computer disk storage system, the 305 RAMAC. The system
can store 5 megabytes and has fifty 24-inch diameter disks.
1961
IBM invents the first disk drive with air bearing heads.
1963
IBM introduces the first removable disk pack drive.
1970
The eight-inch floppy disk drive is introduced.
1973
IBM creates the model 3340 Winchester sealed hard disk drive, the predecessor
of all current disk drives. It has two spindles each with a capacity of 30
MBytes.
1980
Seagate Technology introduces the first hard disk drive for microcomputers,
the ST506. It can hold 5 Mbytes.
Phillips introduces the first optical laser drive.
1986
Integrated Drive Electronics (IDE) technology was proposed. It is a standard
which controls the flow of data between the processor and the hard disk.
IDE is not itself an actual hardware standard, but the proposals were integrated
into an industry-agreed interface specification known as ATA (AT Attachment).
ATA defines a command and register set for the interface, creating a universal
standard for communication between the drive unit and the PC.
The SCSI specification is completed. It is a bus which controls the flow
of data between the processor and its peripherals. It can handle up to
eight devices such as hard disks, CD-ROM drives, printers, scanners, etc.
1988 Redundant Arrays of Inexpensive Disks (RAID) is proposed. The original
concept was to cluster small inexpensive disk drives into an array so
that the array could appear to the system as a single large expensive
drive. Such an array was found to have better performance characteristics
than an individual hard drive. Subsequent development of RAID resulted
in six standardized RAID levels to offer a combination of performance
and data protection (example below).
Level 0 provides 'data striping' (spreading out blocks of each file across
multiple disks) but no redundancy. This improves performance but does not
deliver fault tolerance. The collection of drives in a RAID Level 0 array
has data laid down in such a way that it is organized in stripes across
the multiple drives, enabling data to be accessed from multiple drives in
parallel.
Level 1 provides disk mirroring, a technique in which data is written
to two duplicate disks simultaneously, so that if one of the disk drives
fails the system can instantly switch to the other disk without any loss
of data or service. RAID 1 enhances read performance, but the improved performance
and fault tolerance are at the expense of available capacity in the drives
used.
Level 3 is the same as Level 0, but 0 sacrifices some capacity,
for the same number of drives, to achieve a higher level of data integrity
or fault tolerance by reserving one dedicated disk for error correction
data. This drive is used to store parity information that is used to maintain
data integrity across all drives in the subsystem.
Level 5 is probably
the most frequently implemented. It provides data striping at the byte
level and also stripe error correction information. This results in excellent
performance coupled with the ability to recover any lost data should any
single drive fail.
1992
SMART (Self-Monitoring, Analysis and Reporting Technology) by IBM is
an industry first. Hard drives equipped with Predictive Failure Analysis
(PFA) can actually predict their own failure.
1993
Western Digital introduces Enhanced IDE (EIDE). It is a standard to overcome
the constraints of ATA. It supports faster data transfer rates and higher
disk capacities. It also supports AT Attachment Packet Interface (ATAPI)
which supports non-disk peripherals such as CD-ROM drives and tape drives.
1997
EIDE's data transfer rate limit was doubled to 33 MBps by the new Ultra ATA.
1999
The Microdrive by IBM, is the world's smallest hard disk drive using a single
one inch diameter platter.
