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Re: Going old-school
07/08/17 06:38 AM
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> I decided to start with the first processor ever and found about the Intel 4004 — > Anniversary Project, it even comes with a browser based visual emulator. Still it's a > black box hard to decipher. Looking on YouTube I found good videos explaining briefly > the patterns I needed to understand what's going on inside a microprocessor. It also > lead me to a great book I wish I could have found during my school years.
It isn't the first processor ever - stop propagating this myth. It's just the first microprocessor sold by Intel. There's lots of confusing terminology and weasel-wording thrown around in this area.
Firstly, let's get our terminology straight. A CPU (central processing unit) fetches/executes an instruction stream. It's a specialisation of a Turing machine in some form. You can implement a CPU with transistors, thermionic valves (vacuum tubes), or integrated circuits (ICs). CPUs definitely predate the 4004. For example the IBM System/360 (direct ancestor of the modern IBM System Z) definitely has a CPU, it was announced in 1964 and delivered a year later.
A microprocessor is a CPU implemented using a single IC or a small number of ICs, depending on who you ask. The 4004 isn't the first microprocessor, either. The 1968 Viatron System 21 used a microprocessor.
The 4004, released in 1971, is probably the first microprocessor sold as an independent product (i.e. sold to customers for integration into their own designs, not only as part of a first-party system). This is a significant milestone, but it doesn't make it the first CPU or microprocessor.
You can also argue that the 4004 isn't really a single-chip microprocessor either. The 4001 ROM, 4002 RAM and other peripheral chips actually do instruction decoding themselves to implement memory access and I/O. The MAME MCS-40 CPU core implements this system behaviour, not just the functionality of the 4004 or 4040 itself.
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