The
term
DEDA refers to the Data Entry
and Display Assembly, which is
the assembly used by the astronauts to enter data into the AGS, or to
see data displayed by the AGS. The DEDA was mounted in the
lower-right portion of the LM's control panel, just in front of the LMP
(Lunar Module Pilot). Recall that in the somewhat odd terminology
employed in the Apollo program, the LMP did not actually pilot the
LM. Rather, the commander piloted the LM from the left-hand
position.
yaDEDA
is an emulation of the DEDA for use with
yaAGS. However, it is
certainly possible for the developer of a LM simulation to develop his
or her own emulation of the DEDA. Indeed, the program
yaDEDA2 has now superceded the
original
yaDEDA program,
although the original is still available if someone was interested in
it. When I refer to "yaDEDA" below, I actually mean to refer
interchangeably to both "yaDEDA" and "yaDEDA2" unless I state
otherwise. For information on developing these kinds of
alternative implementations, you should refer to the
developer info
page. You'll notice that the screenshot of
yaDEDA to the right is somewhat
different from the drawing of the DEDA above, particularly as to the
HOLD-key; that's because of discrepancies in the available
documentation, so feedback on this issue is particularly welcome.
Unlike the DSKY, which is basically completely useless without the AGC,
the DEDA has some built-in smarts. Actually, most of the DEDA
user-interface is built into the DEDA, and so
yaDEDA can be operated even without
the presence of
yaAGS.
Notice that the DEDA has two displays: a three-digit display
which is an octal "address", and a 5-digit display (plus sign) of
"data". Quite a lot of the operation of the DEDA was simply to
enter an address (in the first 512 bytes of AEA memory), after which
the AEA would output the value of that memory location every
half-second. The AEA software would format the data, which could
be either octal or decimal, or could involve various scale factors or
units. However, the units and scaling and octal vs. decimal
choices are hardcoded into the AEA software, and are not selectable by
the user. This mode persists until pressing the HOLD key, which
signals the AEA software to stop outputting data. (After hitting
HOLD, you could hit READOUT again to restart the
data-monitoring.) To put the DEDA/AEA in this continuous readout
mode, you do the following on the DEDA keypad:
CLR
OctalDigit
OctalDigit OctalDigit READOUT
The digits appear on the address display as you enter them. Any
error in entering this sequence causes the OPR ERR lamp to light,
making the DEDA basically inoperative until the CLR key is pressed
again. All of this, except for the actual generation of the data,
occurs within the DEDA without needing an AEA (
yaAGS).
The other thing you can do with the DEDA user interface is to perform
data entry: i.e., to send the AEA a command or data. The
interpretation of the data you enter is dependent on the address you
enter:
CLR OctalDigit
OctalDigit OctalDigit Sign Digit Digit Digit Digit Digit
ENTR
Again, both the 3-octal-digit address and the 5-digit data (plus sign)
appear on the display as you strike the keys, but any departure from
the above sequence lights the OPR ERR lamp, which can only be cleared
with CLR. The 5-digit data can be either octal or decimal, but
this is address-dependent (as hardcoded into the AEA software), so it's
not a matter of your choice. Other than the actions which this
type of operation is supposed to cause within the AEA, all of this
takes place within
yaDEDA.
The command-line syntax for the
yaDEDA2
or
yaDEDA program is:
yaDEDA2
[OPTIONS]
or
yaDEDA [OPTIONS]
The
presently-defined options are:
--help
Display a list of options, something
like the information shown here.
--ip=
addr
yaDEDA
and yaAGS are a client/server
pair, and can be running on the same computer or on different
computers. In order to connect to the yaAGS
server, yaDEDA has to know the
IP-address of the machine on which yaAGS
is running. By default this is "localhost"---i.e., the two are running
on the same computer. However, a different IP address may be specified
using this command-line switch. In Linux, this may be either the
machine's name, or else a numerical address in dotted format (n.n.n.n).
MS-Windows---at least Windows 98---is somewhat crippled in this
respect, and will only accept a host name rather than a numerical IP
address.
--port=
port
Similarly (see above), in addition to
an IP address, a port number is needed. This must be in the range of
port numbers
yaAGS is scanning
(which by default is 19897-19906). If no port is specified,
yaDEDA will use 19897, in accordance
with the suggested port assignments on the
developer
page.
--half-size
yaDEDA's
graphical interface is simply too big for PCs with lower graphical
resolution (smaller than 1024×768). If the --half-size
switch is used, half-size graphics are used, and so the interface
should be usable even down to 640×480 resolutions. The
smaller interface doesn't really look very good, because it is
simply blindly scaled down from the larger interface, rather than being
optimized, but at least it's usable at 800×600 and 640×480
resolutions.
--delay=
Milliseconds
Adds a delay at start-up, so that
yaDEDA
does not immediately begin attempting to communicate with
yaAGS. The current defaults
are 0 ms. in Linux and 500 ms. in Win32. This "feature" has been
added as a temporary work-around for
problem
report #23, and probably has no other sensible purpose. Even
on Win32 it isn't usually needed, but it's here for the 10% (or
whatever) of the time it's needed.
--relative-pixmaps
(Final version of yaDEDA only; not available on yaDEDA2.) Alters the locations
of graphics files used by the yaDEDA
program to the ./pixmaps/yaDEDA/ folder rather than the default system
folders. This makes the program compatible with the directory
structures and runtime assumptions of the VirtualAGC GUI system rather than
the previously used script-driven runtime system.