[Info-vax] Hard links on VMS ODS5 disks

[Johnny Billquist]

On 2023-07-27 19:08, bill wrote:
> On 7/27/2023 8:46 AM, Johnny Billquist wrote:
>> On 2023-07-27 02:05, bill wrote:
>>> On 7/26/2023 2:33 PM, Rich Alderson wrote:
>>
>>>> Ha!  I still make a living programming in Macro-{10,20}, because 
>>>> certain tools
>>>> are written in it and nothing else will do.
>>>>
>>>
>>> Wait a minute.  Are you saying you still make a living supporting 
>>> SYSTEM-10 and SYSTEM-20 computers and not just hobbyist machines?
>>>
>>> Brings up  yet another question, I guess.
>>>
>>> I have always wondered why they created the VAX instead of continuing
>>> development of the PDP-11. I mean, look what INTEL did taking the 8080
>>> (or maybe even the 8008) all the way to x86-64.
>>
>> You could argue that this is what DEC did. Except they eventually 
>> dropped PDP-11 support in hardware and moved it to software emulation,
> 
> Sorry, I certainly don't see it that way.  I see nothing in the VAX that
> reminds me of the PDP-11.

I am surprised by that statement. The VAX feels so much like a mutated 
PDP-11 it's ridiculous, in my opinion.
The compatibility mode is fairly straight forward because of this.

>> and then dropped it altogether. Which just suggest they didn't think 
>> there was enough value to keep it around.
>> And doing explicitly as a compatibility mode allowed for a cleaner 
>> design than what Intel did with the 8080.
>> I assume you haven't missed all the cursing of that architecture.
> 
> I worked with 8080's and Z80's (yes, I know that's not Intel).  They
> were just fine.  Unlike the 6502 which I thought was a piece of crap.

The Z80 is definitely better than the 8080. But the cursing wasn't that 
much about the original CPU, but all the expansions and extensions, 
while still being backward compatible, leading to a CPU today that is a 
bit of a nightmare. Both for programmers and developers of silicon.

There is a reason very few wants to work in assembler on it...

>>> But now I have to wonder why they didn't just continue development of
>>> the 10 and 20.
>>
>> Do you really want to open up that wound again? :-D
> 
> I would love to see what the performance would be for any of these
> processors made with today's tech.  I think even without growing
> memory size they would be more than adequate and probably a lot
> better than some of the Windows Servers running applications today.

It's not a design that easily lends itself to performance. It's a nice 
architecture to write in assembly on.

Windows Servers is actually about software, and not hardware. And yes, 
TOPS-20 is way nicer than Windows...

Memory wasn't particularly a problem on the PDP-10, for sure. But 
portability of software was a bit more of a headache.
And performance...

   Johnny