🚀 go-pugleaf

On 2018-07-15 12:17, Johnny Billquist wrote:
> On 2018-07-15 12:03, Huge wrote:
>> On 2018-07-15, Johnny Billquist <b...@softjar.se> wrote:
>>> On 2018-07-15 01:59, Bob Eager wrote:
>>>> On Sat, 14 Jul 2018 21:22:17 +0200, Johnny Billquist wrote:
>>>>
>>>>> Disk directly to buffers in user space in Linux? Sure, it's called 
>>>>> mmap.
>>>>> Which, by the way, is more or less a direct ripoff from TOPS-20.
>>>>
>>>> Which was a ripoff from MULTICS and EMAS.
>>>
>>> I'm not sure about that. Multics, from what I read, considered memory
>>> and files to be the same thing. This is sort of a different idea than
>>> saying that you can map a file into a specific part of your memory. I
>>> have no idea how or what EMAS is. :-)
>>>
>>> But the comment about the ripoff goes as far as the Unix mmap API being
>>> pretty much a copy of TOPS-20.
>>
>> I find the word "ripoff" problematical. Virtually everything in computer
>> science is based on something else. Thinking "that's a good idea" and
>> re-using it in a new and interesting way is hardly "ripping off".
> 
> If you take the concept *and* API and copy it verbatim, I think calling 
> it a ripoff is not so wrong.
> Had they just taken the concept, then I'd say inspired by, or something 
> similar. But this one goes a bit further. I remember back when Sun 
> introduced mmap, that I heard (don't remember from where), that they had 
> looked at TOPS-20 when they did the implementation for SunOS.

I should probably modify my language.
For many, "verbatim" is probably hard to justify here. After all, the 
TOPS-20 PMAP% system call is an API from assembly language, while the 
Unix mmap() system call is an API from C.

Also, PMAP% have some additional features and functions that mmap() does 
not.
mmap() is maybe more properly described as a subset of PMAP% in one way.

But mmap() is essentially exactly the same as PMAP%.

   Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: b...@softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol