[retrac]

Discrete is the opposite of integrated, as in integrated circuit.

In practice, it means using multiple components. In a strict sense it means no integrated circuits at all, I suppose. But it's also a relative thing. So while a 7400 series chip is not a "discrete" component as most would think of it, using a hundred 7400 series chips to implement a processor is relatively more discrete than a microprocessor. (It's certainly not as integrated.)

Since the early 1980s, Ethernet interfaces have used used custom chips, because the amount of logic required would need dozens of gate-level chips otherwise (as seen here!)

[__d]

In the early 1980s, an Ethernet adaptor required a lot of board space. They were often of similar complexity to the main CPU board. For example, this is DEC's first Unibus Ethernet: https://gunkies.org/w/images/1/16/DEUNA.jpg, which occupied two boards.

The software required to run a TCP/IP stack was also large, limiting the system to a handful of active sockets, and consuming large parts of the available CPU power to run something like Telnet or FTP.

It took a few years for CPUs to get more powerful, more RAM to become affordable, and for network hardware to become integrated onto the smaller boards like ISA or NuBus.

[mogoh]

ah, that makes sense. Thanks!