History and the growth of computer memory storage

The growth of the computers and the computer industry has exploded in the last 10-15 years. Nowadays we are used to having hundreds of gigabytes of storage capacity in our computers. Lets take a look back in History of  the growth of computer memory storage.

Selectron tubes


x2811946 RCA started the development of the Selectron tube. It was an early form of computer memory and the largest selectron tube measured 10 inches and could store 4096 bits. As these tubes were very expensive, they were very short-lived on the market.


Drum memory

08b392d3814522af2ff28d6185dc0836Invented 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.

Drum memory, an early form of computer memory that actualy did use a drum as a working part with data loaded to the drum. The drum was a metal cylinder coated with recordable ferromagnetic material. The drum also had a row of read-write heads that wrote and then read the recorded data.






Magnetic core memory (ferrite-core memory)

Magnetic core memory (ferrite-core memory) is another early form of computer memory. Magnetic ceramic rings called cores, stored information using the polarity of a magnetic field.

It uses tiny magnetic toroids (rings), the cores, through which wires are threaded to write and read information. Each core represents one bit of information. The cores can be magnetized in two different ways (clockwise or counterclockwise) and the bit stored in a core is zero or one depending on that core’s magnetization direction. The wires are arranged to allow an individual core to be set to either a “one” or a “zero”, and for its magnetization to be changed, by sending appropriate current pulses through selected wires. The process of reading the core causes the core to be reset to a “zero”, thus erasing it. This is called destructive readout.

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).


300px-fig9-dickinsonibm350diskstorageramacIBM 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.

Magnetic tape

ph2401In the 1950s magnetic tapes was first used by IBM to store data on magnetic tape. Since one roll of magnetic tape could store as much data as 10 000 punch cards it became an instant success and became the most popular way of storing computer data until the mid 1980s.

The Compact Cassette

250px-tdkc60cassetteThe Compact Cassette is of course one kind of magnetic tape but since so many of us have used them, it deserves a special section. The Compact Cassette was introduced by Philips in 1963 but it wasn’t until the 1970s it became popular. Computers like the ZX Spectrum, the Commodore 64 and the Amstrad CPC used the cassettes to store data. A standard 90 minutes Compact cassette could store around 700kB to 1MB of data on each side of the tape.

floppy disk

102716265p-03-03In 1969 the first floppy disk was introduced. It was a read-only 8 inch disk that could store 80kB of data. 4 years later, in 1973, the a similar floppy disk with the same size could store 256kB of data plus it was possible to write new data again and again. Since then the trend has been the same – smaller floppy disks that could store more data. In the late 1990s you could get ahold of 3 inch disks that could store 250 MB of data.

The Laserdisc

videodiscWe 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.

World’s first hard drive

18mpc38rrnmmfjpgIBM unveiled the 305 RAMAC on September 13th, 1956. The computer was nothing but a revolution since it could store up to 4.4MB of data (5 million characters) – an enormous amount of data back then. The data was stored on fifty 24 inch magnetical disks. More than 1000 systems were built and the production ended in 1961. IBM leased the computers for $3 200 per month.




hard drive

serwis-dyskowThe hard drive is still a product that is under constant development. The Hitachi Deskstar 7K500 that you can see on the image above is the first hard disk drive that can store 500 GB of data – or approxmiately 120 000 times more data than the world’s first hard drive IBM 305 RAMAC. The trend is crystal clear; for each year we get cheaper drives that can store more data faster.