Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!mcnc!rti!bcw
From: bcw@rti.UUCP (Bruce Wright)
Newsgroups: comp.sys.ibm.pc
Subject: Re: High- vs. low-level languages (Was: Re: Why unix doesn't catch on)
Summary: FTN on the CDC 6000
Message-ID: <2971@rti.UUCP>
Date: 18 May 89 14:32:12 GMT
References: <664@tukki.jyu.fi> <360014@hplvli.HP.COM>
Organization: Research Triangle Institute, RTP, NC
Lines: 24

In article <360014@hplvli.HP.COM>, boyne@hplvli.HP.COM (Art Boyne) writes:
> phil@ux1.cso.uiuc.edu writes:
> 
> Years ago, the guy at Purdue University who supported all the compilers
> and assembler (all written in assembler!) for the main computer center
> told me that the CDC 6000 series FTN compiler with maximum optimization
> would produce only about 10-20% more code than a GOOD assembly language
> programmer - this was considered excellent.  I have yet to see a C
> compiler match this.

Ah, memories of undergraduate days using FTN on a CDC 6600.... a really
great machine in its day .... but I digress.

The CDC 6000 series had a rather strange architecture - in some ways 
somewhat RISC-like (plus ca change, plus c'est la meme chose).  Each
word was 60 bits, and instructions could be 15 or 30 bits but could not
cross a word boundary.  One of the compiler's main problems would be 
re-arranging code to fill each 60-bit word completely to avoid having
to insert PASS (no-operation) instructions (a problem similar to the 
delayed branch problem on many RISC machines).  Programming the 6000 
in assembler would be possible but somewhat disorienting for most 
assembler programmers.

						Bruce C. Wright