20 Jun
2018
20 Jun
'18
4:55 a.m.
Does the screen count as I/O?
I’d suggest that it’s just that the balance is (intentionally) quite different. If you
squint right, a GPU could look like a channelized I/O controller.
d
On 20 Jun 2018, at 06:45, Peter Jeremy
<peter(a)rulingia.com> wrote:
On 2018-Jun-18 10:25:03 +0100, Tim Bradshaw
<tfb(a)tfeb.org> wrote:
Apropos of the 'my iPhone has more power than our System-360/50, but it has nowhere
near the sheer I/O throughput of a mainframe' comment: there's obviously no
doubt that devices like phones (and laptops, desktops &c) are I/O-starved compared to
serious machines, but comparing the performance of an iPhone and a 360/50 seems to be a
matter of choosing how fine the dust you want the 360/50 to be ground into should be.
The 360/50 could, I think, transfer 4 bytes every 2 microseconds to/from main memory,
which is 20Mb/s. I've just measured my iPhone (6): it can do about 36Mb/s ... over
WiFi, backed by a 4G cellular connection
One way of looking at this actually backs up the claim: An iPhone has maybe
3 orders of magnitude more CPU power than a 360/50 but only a couple of
times the I/O bandwidth. So it's actually got maybe 2 orders of magnitude
less relative I/O throughput.
--
Peter Jeremy