"Your laptop is more powerful than you realize," writes a reader.
People often think that we have more computer power than we did in the 1960s. Those comparisons tend to underestimate the difference.
In 1961, a few universities around the world had bought IBM 7090 mainframes, according to the article written by the former director of MIT's CSAIL. The first line of all-transistor computers, the 7090, cost US $20 million in today's money, or about 6,000 times as much as a top-of-the-line laptop today. The computers were usually used as a shared resource for the entire campus. Few users were lucky enough to get an hour of computer time per week.
The 7090 had a clock cycle of 2.18 microseconds, so the operating Frequency was 500 kilohertz. Most of the time it took more than one cycle to execute instructions in those days. A floating-point operation could take up to 15 cycles. The 7090 is thought to have executed 100,000 instructions per second. Modern computer cores can operate at a sustained rate of 3 billion instructions per second, with much faster peak speeds. A modern chip with four or eight cores is 100,000 times faster.
You can run your laptop all the time, which is more than 1,900 years of computer time every week, unlike the person who got an hour of computer time in 1961.
This comparison is unfair to the computers of today. 16 gigabytes of main memory is what your laptop has. The 7090 was maxed out at over 140 kilobytes. It would take a lot of shuffling of data into and out of the 7090 to run the same program. The best tape drives had maximum data transfer rates of 60KB per second. The rate needed to be shared among them because 12 tape units could not be attached to a single computer. To read 16 gigabytes of data in this way would take three days, and a group of human operators swap tapes on the drives. Data transfer was slower by 100,000 compared to today's rate.
The 7090 seems to have run at about 10 - 15 the speed of your laptop. The age of the universe on 7090 would take a week more to complete than a week on a modern laptop.
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