DMA transfer was just unwilingness to do more complex implementation.
PC was no more constained than 360/30, where simultaneous I/O
and computation was common.
According to Waldek Hebisch <antispam@fricas.org>:
DMA transfer was just unwilingness to do more complex implementation.
PC was no more constained than 360/30, where simultaneous I/O
and computation was common.
Actually it wasn't. The /30 shared the microengine between the CPU and
the channel. When the channel was doing disk I/O the CPU pretty much stopped.
In practice that was fine, BOS and DOS only ran one program at a time
so it'd usually be waiting for the I/O to finish anyway.
In practice that was fine, BOS and DOS only ran one program at a time
so it'd usually be waiting for the I/O to finish anyway.
Definitely not. In my day DOS had three partitions. Batch ran in BG, but
FG1 might run a spooler or a simple TP program like MTCS. Now there are
more partitions, but no more /30s.
According to Peter Flass <Peter@Iron-Spring.com>:I worked where we had a 360/30 with 96K with DOS. We ran BG plus a
In practice that was fine, BOS and DOS only ran one program at a time
so it'd usually be waiting for the I/O to finish anyway.
Definitely not. In my day DOS had three partitions. Batch ran in BG, but
FG1 might run a spooler or a simple TP program like MTCS. Now there are
more partitions, but no more /30s.
DOS could certainly have three partitions, but I doubt many people used them on
a 360/30. Multiprogramming needed storage protection, which was an extra cost option on the /30, and at least 32K, but you could get a /30 with 16K or 24K.
Spooling wouldn't make much sense on a machine so slow that it stops when it reads or writes anything. The manual says that "Execution of instructions is suspended until the completion of data transfers for buffered devices" which included most printers and card readers.
It normally only came with a multiplexor channel, which a disk or tape captured
for the length of the operation so it couldn't do disk or tape I/O and any other
I/O at the same time unless you paid extra for a selector channel.
You could run OS on a 64K /30, but only single threaded PCP, not MFT or MVT.
According to Peter Flass <Peter@Iron-Spring.com>:We had a spooler on 360/30 and it made a difference. The program would
In practice that was fine, BOS and DOS only ran one program at a time
so it'd usually be waiting for the I/O to finish anyway.
Definitely not. In my day DOS had three partitions. Batch ran in BG, but
FG1 might run a spooler or a simple TP program like MTCS. Now there are
more partitions, but no more /30s.
DOS could certainly have three partitions, but I doubt many people used them on
a 360/30. Multiprogramming needed storage protection, which was an extra cost option on the /30, and at least 32K, but you could get a /30 with 16K or 24K.
Spooling wouldn't make much sense on a machine so slow that it stops when it reads or writes anything. The manual says that "Execution of instructions is suspended until the completion of data transfers for buffered devices" which included most printers and card readers.
It normally only came with a multiplexor channel, which a disk or tape captured
for the length of the operation so it couldn't do disk or tape I/O and any other
I/O at the same time unless you paid extra for a selector channel.
You could run OS on a 64K /30, but only single threaded PCP, not MFT or MVT.
It normally only came with a multiplexor channel, which a disk or tape capturedspooler in FG.
for the length of the operation so it couldn't do disk or tape I/O and any other
I/O at the same time unless you paid extra for a selector channel.
You could run OS on a 64K /30, but only single threaded PCP, not MFT or MVT. >I worked where we had a 360/30 with 96K with DOS. We ran BG plus a
According to Peter Flass <Peter@Iron-Spring.com>:
In practice that was fine, BOS and DOS only ran one program at a time
so it'd usually be waiting for the I/O to finish anyway.
Definitely not. In my day DOS had three partitions. Batch ran in BG, but
FG1 might run a spooler or a simple TP program like MTCS. Now there are
more partitions, but no more /30s.
DOS could certainly have three partitions, but I doubt many people used them on
a 360/30. Multiprogramming needed storage protection, which was an extra cost option on the /30, and at least 32K, but you could get a /30 with 16K or 24K.
Spooling wouldn't make much sense on a machine so slow that it stops when it reads or writes anything. The manual says that "Execution of instructions is suspended until the completion of data transfers for buffered devices" which included most printers and card readers.
It normally only came with a multiplexor channel, which a disk or tape captured
for the length of the operation so it couldn't do disk or tape I/O and any other
I/O at the same time unless you paid extra for a selector channel.
You could run OS on a 64K /30, but only single threaded PCP, not MFT or MVT.
According to geodandw <geodandw@gmail.com>:
It normally only came with a multiplexor channel, which a disk or tape capturedI worked where we had a 360/30 with 96K with DOS. We ran BG plus a
for the length of the operation so it couldn't do disk or tape I/O and any other
I/O at the same time unless you paid extra for a selector channel.
You could run OS on a 64K /30, but only single threaded PCP, not MFT or MVT.
spooler in FG.
The most IBM offered on a /30 was 64K, but I have heard of aftermarket vendors that
managed to activate another address line or two and put on more memory. If your
employer did that, they probably also got the extra cost selector channel that let
the disk run in parallel with other stuff.
So I believe you, but that was a fairly unsuual and very large configuration for a /30.
John Levine <johnl@taugh.com> writes:
According to Peter Flass <Peter@Iron-Spring.com>:
In practice that was fine, BOS and DOS only ran one program at a time
so it'd usually be waiting for the I/O to finish anyway.
Definitely not. In my day DOS had three partitions. Batch ran in BG, but >>> FG1 might run a spooler or a simple TP program like MTCS. Now there are
more partitions, but no more /30s.
DOS could certainly have three partitions, but I doubt many people used them on
a 360/30. Multiprogramming needed storage protection, which was an extra cost
option on the /30, and at least 32K, but you could get a /30 with 16K or 24K.
Spooling wouldn't make much sense on a machine so slow that it stops when it >> reads or writes anything. The manual says that "Execution of instructions is >> suspended until the completion of data transfers for buffered devices" which >> included most printers and card readers.
It normally only came with a multiplexor channel, which a disk or tape captured
for the length of the operation so it couldn't do disk or tape I/O and any other
I/O at the same time unless you paid extra for a selector channel.
I don't believe I ever worked with a 30 without storage protection, or
less than 64K. A typical COBOL program would use a lot of that 64K.
You could run OS on a 64K /30, but only single threaded PCP, not MFT or MVT.
OS on a 30? No way!
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