The Selectron tube
The Selectron tube had a capacity of 256 to 4096 bits (32 to 512 bytes). The 4096-bit Selectron was 10 inches long and 3 inches wide. Originally developed in 1946, the memory storage device proved expensive and suffered from production problems, so it never became a success.
The Selectron vacuum tube, is the only technology listed here that was not for secondary (permanent) storage. Selectrons were used for primary data storage, like a modern computer’s RAM.
Above: The 1024-bit Selectron.
- 300px-Selectron256Xsection.jpg (13.64 KiB) Viewed 8235 times
Punch cards
Early computers often used punch cards for input both of programs and data. Punch cards were in common use until the mid-1970s. It should be noted that the use of punch cards predates computers. They were used as early as 1725 in the textile industry (for controlling mechanized textile looms).
Above: Card from a Fortran program: Z(1) = Y + W(1)
Above left: Punch card reader. Above right: Punch card writer.
Punched tape
Same as with punch cards, punched tape was originally pioneered by the textile industry for use with mechanized looms. For computers, punch tape could be used for data input but also as a medium to output data. Each row on the tape represented one character.
Above: 8-level punch tape (8 holes per row).
Magnetic drum memory
Invented all the way back in 1932 (in Austria), it was widely used in the 1950s and 60s as the main working memory of computers. In the mid-1950s, magnetic drum memory had a capacity of around 10 kB.
Above left: The magnetic Drum Memory of the UNIVAC computer. Above right: A 16-inch-long drum from the IBM 650 computer. It had 40 tracks, 10 kB of storage space, and spun at 12,500 revolutions per minute.
The hard disk drive
The first hard disk drive was the IBM Model 350 Disk File that came with the IBM 305 RAMAC computer in 1956. It had 50 24-inch discs with a total storage capacity of 5 million characters (just under 5 MB).
Above: IBM Model 350, the first-ever hard disk drive.
The first hard drive to have more than 1 GB in capacity was the IBM 3380 in 1980 (it could store 2.52 GB). It was the size of a refrigerator, weighed 550 pounds (250 kg), and the price when it was introduced ranged from $81,000 to $142,400.
Above left: A 250 MB hard disk drive from 1979. Above right: The IBM 3380 from 1980, the first gigabyte-capacity hard disk drive.
The Laserdisc
We mention it here mainly because it was the precursor to the CD-ROM and other optical storage solutions. It was mainly used for movies. The first commercially available laserdisc system was available on the market late in 1978 (then called Laser Videodisc and the more funkily branded DiscoVision) and were 11.81 inches (30 cm) in diameter. The discs could have up to 60 minutes of audio/video on each side. The first laserdiscs had entirely analog content. The basic technology behind laserdiscs was invented all the way back in 1958.
Above left: A Laserdisc next to a regular DVD. Above right: Another Laserdisc.
The floppy disc
The diskette, or floppy disk (named so because they were flexible), was invented by IBM and in common use from the mid-1970s to the late 1990s. The first floppy disks were 8 inches, and later in came 5.25 and 3.5-inch formats. The first floppy disk, introduced in 1971, had a capacity of 79.7 kB, and was read-only. A read-write version came a year later.
Above left: An 8-inch floppy and floppy drive next to a regular 3.5-inch floppy disk. Above right: The convenience of easily removable storage media.
Magnetic tape
Magnetic tape was first used for data storage in 1951. The tape device was called UNISERVO and was the main I/O device on the UNIVAC I computer. The effective transfer rate for the UNISERVO was about 7,200 characters per second. The tapes were metal and 1200 feet long (365 meters) and therefore very heavy.
Above left: The row of tape drives for the UNIVAC I computer. Above right: The IBM 3410 Magnetic Tape Subsystem, introduced in 1971.
Twistor Memory
Twistor is a form of computer memory, similar to core memory, formed by wrapping or closing magnetic tape around a current-carrying wire. Although the developers, Bell Labs, had high hopes for Twistor, it was used for only a brief time in the marketplace between about 1968 and the mid-1970s. In this period all previous forms of memory were quickly replaced by semiconductor memory chips, which were considerably faster and less expensive. Twistor is largely the brainchild of a single person, Andrew Bobeck, who later developed bubble memory after generalizing some of the concepts used in Twistor.
Bubble Memory
Bubble memory is a type of non-volatile computer memory that uses a thin film of a magnetic material to hold small magnetized areas, known as bubbles or domains, each of which stores one bit of data. Bubble memory started out as a promising technology in the 1970s, but failed commercially as hard disk prices fell rapidly in the 1980s.
- 250px-Bubblememory.jpg (14.26 KiB) Viewed 8235 times
Thin-film Memory
Thin-film memory is a high-speed variation of core memory developed by Sperry Rand in a government-funded research project.
Instead of threading individual ferrite cores on wires, thin-film memory consisted of 4 micrometre thick dots of permalloy, an iron-nickel alloy, deposited on small glass plates by vacuum evaporation techniques and a mask. The drive and sense lines were then added using printed circuit wiring over the alloy dots. This provided very fast access times in the range of 670 nanoseconds, but was very expensive to produce.
In 1962, the UNIVAC 1107, intended for the civilian marketplace, used thin-film memory only for its 128-word general register stack. Military computers, where cost was less of a concern, used larger amounts of thin-film memory. Thin film was also used in a number of high-speed computer projects, including the high-end of the IBM System/360 line, but general advances in core tended to keep pace.
Compact Cassette
And of course, we can’t mention magnetic tape without also mentioning the standard compact cassette, which was a popular way of data storage for personal computers in the late 70s and 80s. Typical data rates for compact cassettes were 2,000 bit/s. You could store about 660 kB per side on a 90-minute tape.
Above left: The standard compact cassette. Above right: The Commodore Datassette is sure to bring up fond memories for people who grew up in the 80s.
There are so many interesting pictures from “the good old days” when you look around on the web. These were some of the best we could find, and we hope you liked them.
Back to the games boys and girls
