DAN@mit-ml.arpa (03/16/83)
From: Dan Blumenfeld <DAN@mit-ml.arpa>
As promised earlier, here's the first installment of info on Apple's LISA
workstation. Each installment will contain stuff from the LISA spec sheets
which I received at the Philly OAC, as well as comments and pointers where
appropriate. I'll also place all of these summaries in one of the MC;CPM
archives.
------------------------------
Hardware Specifications: Apple LISA
Display: 12 inch (diagonal) screen
Bit mapped display: 720 x 364
Up to 45 lines of 144 characters
<comment: these are VERY small chars; chars will usually be larger>
60 Hz refresh rate
Keyboard: Detached, N-key rollover, sculptured keycaps
Full ASCII Character set
<comment: no "CONTROL" key, command key may be used as such for
terminal emulation>
Numeric Keypad
All keys are programmable
<comment: keyboard under control of NS COPS processor>
Mouse: Optomechanical, using small "trackball" and shaft encoders
One button
<comment: One button was selected to elimiate confusion>
<comment: Small Trackball may be removed for cleaning>
Main Processor: MC68000
CPU running at 5 MHz
<comment: 5 MHz operation required because video controller cycle
steals memory from the CPU to provide streakless display>
Main Memory: 1 Megabyte RAM, with parity checking
16K bytes of boot ROM
<comment: Operating System locks out bad blocks of RAM>
Disk storage: Two 5 1/4" floppy disk drives, 860K each
<comment: Drives are VERY non-standard, and use CLV
for constant density>
ProFile 5 Mb hard disk
<comment: ProFile contained in seperate cabinet>
Automatic disk eject and head loading under software control
Uses MOS6504 as controller
Memory Management: Segmentation into 128 variable length blocks
dynamically controlled through memory map table
Operating System may relocate segments in memory
Provides access controls for blocks of memory
Comm I/O: Two serial I/O ports
Supports async, bisync, SDLC, and HDLC
RS-232, half or full duplex, with full modem control on one port
Baud rate and other attributes under software control
One parallel Port, MOS6522 I/O chip
8 bit bidirectional port with handshake signals
Real Time Clock: Interval and event timing
Time of Day Clock
Software on-off control
Battery Backup
Audio Output: Built-in Speaker with software controllable oscillator
Expansion board slots: Three slots, ZIF connectors
Access to system bus
DMA, Memory Mapped I/O, and Vectored Interrupts
+5 V, -5 V, +12 V, and -12 V provided
Weight and Physical Dimensions:
Main Unit: Weight: 48 lbs (22 kg)
Height: 13.8 inches (350 mm)
Width: 18.7 inches (475 mm)
Depth: 15.2 inches (388 mm)
Keyboard: Weight: 4 lbs (1.8 kg)
Height: 2.7 inches (68 mm)
Width: 18.7 inches (475 mm)
Depth: 6.5 inches (165 mm)
<comment: Main unit with keyboard under front has depth of 16 inches (403 mm)>
Power Requirements: 115 or 230 VAC
48 to 68 Hz
270 Watts Maximum
Environmental Requirements: Ambient Operating Temp: 40F-108F (5C-42C)
Relative Humidity: 15-80% noncondensing
<comment: Main unit is convection cooled, no fan>
----------
Additional Comments and Observations:
>From a servicing standpoint, the LISA is a dream. The whole unit,
except for the monitor, is modular and snaps apart, including the
drives. So, for ultimate realiablity, one could keep spare boards and
drives on hand. The diagnostics are quite extensive, and can determine
specific faults under most circumstances.
The CRT has a non glare shield on it, and the picture is very sharp.
Brightness and contrast are software controllable.
While the LISA has alot of memory and uses a 68000, the hardware specs
are acceptable, but by no means revolutionary (or even special).
Apple claims that the "Twiggy" floppy drives have a very low error rate.
I guess this was a problem in 1980, when the LISA was being designed, but
what they wound up with is a drive not significantly more reliable than a
Tandon DDDS 5 1/4" floppy, but COMPLETELY non-standard. One of the
problems with the old double sided drives was excessive media wear from
both heads touching the diskette at about the same place. Drive
manufacturers performed "Tap Tests" to see how many head loads and unloads
were required before the diskettes and/or heads gave out. Apple's
solution to this problem was to put the top and bottom heads on opposite
sides of the diskette. So, what you have is a 5 1/4" diskette with two
slots for heads, one in the normal place, and the other where the label
normally goes. Other companies, such as Tandon, solved the problem by
always having the heads loaded. It turns out that this is much easier
on both the heads and the diskettes, and removes the need for a head
load solenoid. Thanks to Apple, we now have a new (yeech!) media
type, not to mention format, because they use CLV rather than CAV, to
keep density constant. I'm sure the magnetic media manufacturers are
overjoyed.
The ProFile hard disk is not exactly what I'd call state-of-the-art...
as a matter of fact, it is pretty slow. The fact that the hard disk
is in a seperate box is another problem, because now you have to put
it somewhere. In summary the LISA would be even nicer if it had one
Thin-Line DDDS Drive and one SyQuest Removable Hard Disk.
What I'm getting at is that the LISA is not amazing from a hardware
standpoint. Rather, it is the software which makes this machine so
flexible and powerful. We'll be looking at the LISA applications
programs in the next installment of this newsletter.
Dan