I'm picking as I've been around long enough in the industry to see what I
call retrorevisionism. It's the terminology creep that has been occuring
since the PC became the computer for all things. Though its been going on
for load longer.
< I don't know why you would want to class that as a MPU. Most of these
< terms were invented because a new breed came into existance and it neede
< a new name to distinguish it from what came before. "Microprocessor"
< was coined to celebrate a logic integration landmark: a computer on a
< single chip.
the terms were invented after the fact.
< > < Microcomputer: a computer based on a single microprocessor.
< >
< > What if there are several performing different tasks in the same box.
<
< OK, Microcomputer: a computer that runs applications on a single
< microprocessor.
Lessee, my visual 1050 uses the 6502 for video and a z80 for the main cpu
and a z80 for the MFM hard disk controller (all running concurrently).
Teh single cpu thing is a sticking point.
Try: A computer based on microprocessors.
< I really don't know what to call a SMP PC, though. Microsupercomputer?
Or the s100 4 z80 loosely coupled SMP running CP/M2.2... Terminology
sorta gets mashed.
< > < Workstation: a computer designed to run Unix with a bitmapped displa
< >
< > What if it's a VAX running VMS? Yes the VS3100s were definatly
< > workststions.
<
< OK, Workstation: a computer with a bitmapped display designed to run a
< non-Microsoft multitasking OS.
;') a NON PC pc.
< > < Minicomputer: a timesharing computer that can support fewer than 10
< > < simultaneous users.
< >
< > VAX and minicomputer that could and often did have more than 100 users
<
< OK, Minicomputer: a general purpose computer without a memory-mapped
< display, smaller than a mainframe.
What about a MicrovaxII servicing a half dozen Xterms? Or a 11/780
equipped with a DECterm100 (bit mapped and the map is vax resident)?
Minicomputer: something significantly smaller and cheaper than mainframes
of the time. The definition was based on compact size not IO interface
or the presence or lack of a bit mapped display.
< > < Mainframe: a timesharing computer than can support 100 or more user
< > < simultaneously.
< >
< > Generally big iron and most that had that distinction where physically
< > large. AKA univac 1180.
<
< OK, Mainframe: a general purpose computer without a memory-mapped displa
< that weighs at least one ton.
Oh dear.. the video displays on some of the big ums... Actually the break
point was again size and especially cost. At the time mini and mainframe
were in vogue the difference was around 10/1 in cost and around the same
or greater for weight.
< Some people use PC's as dedicated controllers, but that doesn't make
< a PC an embedded computer in my mind. Cross-development seems to be th
< only common factor when people talk about embedded, although there are
< embedded environments, such as QNX, that support native development.
PDP-8s and 11s were some of the mainstays for embedded controls work
and some had local resources enough to develop insitu. Your viewpoint
is influenced by the current vogue. ***An embedded system is simply a
system that has a computer (ANY!) burried/coupled to it.*** It could be
a NC mill with a PDP-8, a production line with a PDP-15 or in later years
a PLC or a process control system with a s100 crate and Compucolor board
and color CRT. I have seen and worked on all of these and more.
Allison