1246 
MONITORING 
nels are several standard peripherals: a 200 
card per minute card reader, a 200 line per min- 
ute line printer, and an ASR-35 teletypewriter. 
Six TEC alphanumeric terminals are positioned 
throughout the facility. These serve as the 
major communication media between T «& E sci- 
entific personnel and the computer. Input from 
the TEC's is through the digital input-output 
channels, since the integrated circuit memories 
of the TEC are used to store operator messages 
and these messages are read and interpreted 
one character at a time. The TEC memories 
thus act as additional computer memory. 
Displays to the TEC are written at high 
speed through a direct memory access channel 
as are analog displays to the Beehive graphic 
terminals. The A/D converter has a maximum 
sample rate of 100,000 samples per second and 
sixty-four channels of multiplexing. It has a 
fourteen bit resolution with an input range of 
minus ten to ten volts. A Beckman Microzone 
Densitometer and twelve physiological channels 
are currently attached to the A/D converter. 
The system disc (RAD) has 750,000 16-bit 
words with an average access time of seventeen 
milliseconds. Several digital instruments are in- 
terfaced through the digital input-output chan- 
nels. These include a Coulter Counter, Radiome- 
ter, Blood Gas Co-oximeter, and SOON 
Spectrophotometer. 
SIGMA-3 MULTI-STATION COMPUTER SYSTEM 
T & E Facility personnel control data acquisi- 
tion, identification, processing and storage with 
TEC terminals distributed throughout the facil- 
ity. The terminal language was deliberately 
made simple, and messages printed on the ter- 
minal help guide facility personnel in its use. 
This allows personnel to learn to use the com- 
puter system quickly and easily, and, thereby, 
allows them to concentrate on the experimental 
or laboratory aspects of their job. Three tjrpes 
of entries may be made at the terminal. These 
types are the context codes referred to earlier, 
data and special symbols. Context codes are 
used to describe to the computer the job to be 
done as well as to identify the data which will 
be collected. Eight context code types are avail- 
able. These are shown in Table I. Keyed in data 
can be alphanumeric or real. The special sym- 
bols will be described as we go through an ex- 
ample. 
System Storage Structure 
Before describing the terminal language and 
how it controls the computer system's opera- 
tion, it is necessary to describe some of the 
major storage structures of the system. 
DAYFILE. The DAYFILE is the major data 
storage media of the Sigma-3. It stores up to 
one full day's data generated from all sources 
under control of the TEC terminal. At the end 
of a day all DAYFILE data are sent to the re- 
mote FIS system where they are entered into 
long term data files. Since all data are entered in- 
to the single DAYFILE structure, it is of course 
essential to adequately identify all data. This is 
done by means of context codes. Seven context 
code types are stored in the DAYFILE. The 
stored context codes have a one-to-one corre- 
spondence with the keyed in context codes but 
are altered in format to be more compatible 
with machine storage and to allow easy access 
to other system structures. Stored data may be 
fixed point, floating point or alphanumeric. All 
DAYFILE entries include an additional identi- 
fier which specifies the number of the terminal 
which caused the generation of the entry. Table 
II is a stylized illustration of a tvpical dayfile 
sequence. For compactness, this illustration as- 
sumes entries from only two keyboards. Each 
data item from a given terminal has its context 
defined by the first previous context of each 
type filed in front of it. Initially all contexts for 
all terrninals are set to zero. If a given item of 
data is identified by a zero context type, it sim- 
ply means that the context type is not applica- 
ble to the data item. Thus, in Table II, the data 
value 7.437 has the contexts : 
Specimen Date 1115 
Event Time 1102 
Animal # 123 
Specimen Time 1005 
Test # 43401 
Staff # 22 
There is no device number assigned to this data 
item since the device code has a 0 value. 
REFERENCE FILE. The REFERENCE 
