IBM 1710 Manual page 38

busy for 12.5 ms. Figure 26 illustrates the timing for
an operation using the Output Printer. The "printer
action time" represents the mechanical operations of
the printer, which can range from merely printing one
character to tabulating across the entire width of a
24-inch carriage. After the
IZ.5-ms interval that the
SIOC
is busy, the
SIOC
Not Busy indicator is turned on,
thereby allowing another input or output operation
to take place during the "printer action time."
If
SIOC
is addressed by an instruction while it is still
busy from a previous operation, the 1620 is interlocked
until the lZ.5-ms
SIOC
operation is complete before pro-
ceeding with the instruction.
When the output unit has completed the indicated
operation with the character transmitted from
IODR)
a signal is generated to turn on the Unit Response
indicator and to initiate an interrupt, which indicates
to the computer that the unit is in response status and
is ready for the next operation.
Input Operation
Transfer of data from an input unit to 1620 core stor-
age is accomplished by two instructions. The first in-
struction, Select Input Channel (SLIC-86), moves the
character to the
IODR;
and the second instruction, Read
Numer'ical Input Channel (RNIC-86) or Read Alpha-
meric Input Channel (RAIC-87), moves the character
from the
IODR
to core storage. The SLIC-86 instruction
must be followed by a RNIC-86 or RAIC-87 instruc-
tion, with no interceding
SIOC
instructions, in order to
prevent loss of the character transferred to the
IODR
by the SLIC instruction.
SELECT INPUT CHANNEL
This instruction selects an address of an input unit and
causes the addressee to place its contents into the
IODR.
This instruction requires an operation code of 86 with
the
QI0
and
Ql1
digits specifying an address of an input
unit. The
Q7
position requires a digit of 5. The P
address is not used.
1620 Write
instruction
200
!-,sec
~
~
Printer Action Timie
r 2 . 3
to
300
ms
SIOC
r---H--,
Channel Busy
I
12.5 ms
L---fJ
I
Load IODR
SIOC
f
Not Busy Indicator
Figure 26. Output Printer Timing
38
READ NUMERICAL INPUT CHANNEL OR
READ ALPHAMERIC INPUT CHANNEL
These two instructions operate similarly except that
one specifies numerical data and the other specifies
alphameric data. Either instruction will cause the con-
tents of
IODR
to be read into core storage. The
Q7
posi-
tion requires a digit 5. The core storage location where
the input character will be stored is the P address.
Note that the Read Numerical instruction contains a
flag over the Op code to distinguish it from the Select
Input Channel instruction.
The squence of operations to transfer an alphameric
or numerical character from an input unit to core stor-
age is as follows:
I. The select instruction sends the input address to
TAS)
which connects the addressed unit to
slOe.
The computer and
TAS
are released for other pro-
gramming after 160
fLsec.
2. Data from the selected input unit is transferred
to
IODR.
This transfer requires 10 ms.
3. At the end of 12.5 ms, the Data Ready interrupt
occurs and a read instruction transfers the data
from
IODR
to core storage.
4. When the input unit is ready to transfer an-
other character to
IODR)
it initiates a Unit Re-
sponse interrupt and turns on the Unit Response
indicator, which remains on until the next select
instruction is given to begin the cycle again.
Transmission of data from the last character position
of the unit removes the input unit from response status.
Execution Times
The time required to transfer a character from core
storage to an output unit or from an input unit to core
storage depends upon the unit involved. Precise instruc-
tion times are provided elsewhere in the manual. The
times provided here are described from the standpoint
of the operation of these units by the process operator.
In operations using the Manual Entry and Sense
Switch input units, the speed of operation would be
limited only by the speed of the process operator in
entering data into the units. The data transfer time is
less than the time it takes the process operator to re-
move his finger from the Execute button.
In operations using the Digital Display Unit, four
data characters and a sign can be transferred to the unit
in less than a second; that is, in less time than it would
take the process operator to read the data or to read
the data and transcribe it on a log sheet.
The speed of the output printer is ten characters
per second, which means that the printing of a line of
output data would normally appear as a continuous
operation. Any time required to tabulate across the