Hacker News Reader

Comment by uecker | Hacker News Reader

The "nor is the hardware a PDP 11". Byte access was the main new feature of the PDP 11 that C adopted. Are you saying being able to access individual bytes is not relevant on modern hardware?

View on HN

Might more mean that we've standardised on a few things like what a byte even is.

The PDP-11 had both 8 and 9-bit bytes. Thats a complexity that few programmers have to touch on, today.

IIRC PDP-11 was a 16 bit word machine with an 8-bit byte. Maybe you remember PDP-10 with 4x9=36 bit words?

Anyway, I do not see how this affects the design of C in a way that makes no sense anymore today (except that one could require CHAR_BIT to be eight, but there are still DSPs where this is not the case). I think people repeat the "the C design reflects the out-dated PDP-11 hardware" meme because it sounds smart while in reality it is just nonsense.

So when is WG14 standardising modern hardware into the C standard?

Basic stuff like SIMD, SIMT, without requiring users to go beyond language extensions, something that any programming language can offer in similar capacity?

Ah, the "what is not standardized does not exist" argument again.

Why does the language standard need to prescribe everything. It is a standardization of between existing compilers, they are allowed and intended to invent things. If anything the experience from C++ has shown, that writing too much behaviour into the standard accidentally has consequences on the possible performance. The C standard is descriptive, not prescriptive.

> something that any programming language can offer in similar capacity?

By your measure a lot of other languages don't offer anything to begin with, because they do not have a standard at all, only a reference implementation.

On the 11, the UNIBUS was 18 bit, the program space was 16 bit, and addressing was 22 bit. So it depended if you were using I-space or D-space.

Actually, if you were mad enough to use the feature, the Dec10 had 6-bit "bytes" - 6 to a word.

It is, however hardly something unique to C, as the C crowd pretends it to be.

Reply on news.ycombinator.com