Old Memory

Yes, I walked a mile through the snow to school. But, that really wasn't such a big deal (still isn't). I lived in a small town where walking was quite safe and there were sidewalks in front of almost every house.

But, in terms of computers, I started programming when the main input media was punched cards (I saved a lot of them for shopping lists for a number of years). When I started college, I worked on a "personal" computer that used punched tape along with toggle switches on the main processing unit. The main storage devices for the larger computers (IBM 360 at first, migrating to IBM 370s before I left) were huge disk drives.

However, memory (as mentioned before) can be categorized into temporary working memory and long-term storage memory. Working memory at that time was core memory -- little magnets that looked like donuts and linked together with copper wires. We still call it core memory after the memory of those days. Most working memory of today is now located within DIMMs (Dual In-line Memory Modules -- see Wikipedia) or, for older systems, SIMMs.

The memory modules have great advantages over old core -- speed, size, and capacity. They also generate much less heat which is both an energy savings as well as a design improvement.

Storage memory is another category which has moved from technology to technology. The first was paper (well, the VERY first was probably clay tablets or chiseled stone). For people, writing or drawing stored the data/information and reading brought it back. It's kind of funny, but efforts have been quite intense over the past twenty years to allow computers to do the same thing that humans have done -- to be able to directly make use of printed text and images.

For early computer systems, it was not possible for the computers to directly use text or drawings. They needed a way to detect a contrast between spaces. This usually meant holes. The holes allowed light, or a mechanical probe, to move through the paper. The areas without holes blocked the light or probe. In this way, the computer could read the "bits" (present/non-present, on/off, 1/0) and save it.

Next came magnetic methods. These were primarily on discs and tapes. The technology of disk drive design has developed enormously over the past 30 years such that a portable disk can hold the same data that a room of luggable, replaceable disks did way back when.

Currently, we are moving farther and farther along to making working memory cost-effective to use as storage memory -- which will lead to the next post on "New and future Memory".