[Robert DeLong]

Just to put it into perspective, PC’s have had for quite some time now, more memory than IBM mainframe models 360 & 370 combined, and each required a big air cooled, dust controlled, room to operate in. But these new chips also improved the mainframes. So while a PC is powerful a mainframe has also gotten much more powerful.

[cynwoody]

Just to put it into perspective, PC’s have had for quite some time now, more memory than IBM mainframe models 360 & 370 combined

The IBM 370 was introduced in 1970, the year before Intel produced the 4004 chip mentioned in the article. The 370 could address a maximum of 16 megabytes of RAM (addresses were 24-bit), however, the machines initially offered maxed out at three megabytes of installed RAM.

In 1983, IBM expanded the 370's address space from 24 bits to 31 bits, making two gigabytes addressable. Why not 32 bits, you might ask? Two reasons:

1. Although RAM had become cheap enough that people wanted more the sixteen megabytes, two gigabytes was still unimaginably large.
2. Pointers in software had all along been stored in 32-bit words, and programmers had become accustomed to using the left-most eight bits to store flags. The most important flag bit was the left-most bit, commonly used to mark the end of a variable-length address list. Usage of the next seven bits was much less common. So, to ease the transition, IBM opted to leave the hi-order bit available as a flag.

[Elsie]

My first computer had 256 BYTES of usable memory.

It loaded info at 300 characters per second.