On 2016-02-21 16:51, Paul Koning wrote:
On Feb 21, 2016, at 7:32 AM, Johnny Billquist <[email protected]> wrote:
On 2016-02-17 21:02, Paul Koning wrote:
On Feb 17, 2016, at 1:55 PM, Larry Baker <[email protected]> wrote:
If you really want the RT-11 experience, try running it off RX01 floppies. My
first experience with DEC PDP-11's was a PDP-11/34 (not 34A; no FPU) running
RT-11 off floppies. Ka-klunk, ka-klunk!
Yes, but that's still quite a lot faster than running it on DECtape.
Still, the amazing part is that RT on DECtape actually works. It's the only
DEC OS I know of for which that is true.
Like others said, lots of PDP-8 systems definitely ran only from DECtape. So
that is not unique by any means.
But more generally - DECtape is just a block addressable mass storage system,
just like any other. In theory, any OS that can run from a disk can just as
well run from DECtape. Speed will be slow, but that's the only thing about it.
True in principle. But a number of OS used a different file structure for
DECtape than for disks -- because of the performance issues. DOS does, for
example, and RSTS copied the DOS DECtape directory structure (but not the disk
one). RT11, on the other hand, uses the same format for both, and the RT11
format works well. That's why RT runs from DECtape without any extra work,
while DOS and RSTS don't.
Interesting. I didn't know that RSTS/E used a different file system for
DECtapes. RSX do not. It's the same file system used on both large
disks, floppies and DECtapes.
RSX do have a few different options on how to deal with disks, but that
has to do with if you have subdirectories on the device or not, and you
can choose how the file system is done for any type of device. It's just
a question of optimizing the layout for different purposes.
Johnny
--
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: [email protected] || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
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