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users manual

digital equipment corporation

DEC-S8-UPTHA-B-D

EPIC
USER'S MANUAL

For additional copies, order DEC-Sk?-UPTHA-B-D from Software Distribution
Center, Digital Equipment Corporation, Maynard, Mass. 01754

First Printing, April 1972
2nd Printing, January, 1973
Reprinted, March, 1973

Your attention is invited to the last two pages
of this document. The "How to Obtain Software
Information" page tells you how to keep up-todate with DEC's software. Completion and return
of the "Reader's Comments" page is beneficial to
both you and DEC; all comments received are
acknowledged and are considered when documenting
subsequent manuals.
Technical changes made since the last printing
are indicated by a line in the margin of the affected page.

@ 1972, 1973 by Digital Equipment Corporation

The material in this manual is for information
purposes and is subject to change without notice.

The following are trademarks of Digital Equipment
Corporation, Maynard, Massachusetts.
DEC
Diqitai
PDP
OS/8

PREFACE

The program described in this manual is part
of the OS/8

software system.

The reader

should be familiar with Chapter 9 ( O S / 8 ) of
Introduction to Programming before using
EPIC.

CONTENTS

Page

1.0

INTRODUCTION

2.0

HARDWARE REQUIREMENTS

3.0
3.1

LOADING E P I C

Restart Procedure

4.0

PAPER TAPE F A C I L I T Y

4.1

Command Format

4.2
4.3
4.4
4.5
4.6

Default O p t i o n s
Error Conditions

2
4
5

L o w Speed I/O

Large Files

Device C o d e s

5.0

EDITING CAPABILITY

5.1
5.2

I n i t i a l Command F o r m a t

E d i t i n g Commands

6.0
6.1

COMPARE C A P A B I L I T Y

Command F o r m a t

7.0

HELP MESSAGE

APPENDIX A

ERROR MESSAGES

A- 1

APPENDIX B

LOADING RTPS FORTRAN I V FROM PAPER TAPE

B- 1

APPENDIX C

PAPER TAPE FORMAT

c- 1

APPENDIX D

LOADING E P I C FROM PAPER-TAPE

D- 1

APPENDIX E

E P I C ASSEMBLY INSTRUCTIONS

E- 1

EPIC

1.0

INTRODUCTION

Edit, Punch and Compare utility program for OS/8, is designed
EPIC, the primarily to assist users by performing the followingfunctions:

1.
2.

Read and punch paper tape files and patches
Edit arbitrary files
Compare files in any format

When EPIC is loaded, the command line determines which function is
desired.
Each of these functions is discussed as a separate topic in this
manual. This manual assumes an elementary knowledge of OS/8.
2.0

HARDWARE REQUIREMENTS

EPIC runs on the minimum hardware configuration required for OS/8.
3.0

LOADING EPIC

To load the EPIC program type R EPIC in response to the OS/8 monitor's
dot ( . ) .
Specify the EPIC function desired by including one of the
following numeric options in the file command line:
P,

1
2

paper tape
edit
compare

Examples :

.R EPIC)
punch the file TRANS stored on
SYS.

-. R EPIC)
-*DTAl:FILEA.SV</l$
.R EPIC)
*DSK:ABC.SWDTAl:XYZ.SV/2$

fetch FILEA from DTAl for editing

compare file ABC on the disk with
file XYZ on DTAl and output block
numbers and locations of each nonmatch on t h e T e l e t y p e .

A f t e r one of t h e s e numeric o p t i o n s has been i n c l u d e i i n a command, it

need n o t be s p e c i f i e d a g a i n i n s u b s e q u e n t s e q u e n t i a l commands r e q u i r i n g t h e same o p t i o n .

S p e c i f y i n g t h e number p u t s E P I C i n a mode and i t

remains i n t h a t mode u n t i l a n o t h e r number i s s p e c i f i e d .
EPIC is set t o option

Initially,

The c h a r a c t e r ALTMODE, which p r i n t s a s $ on

t h e T e l e t y p e ’ , i s u s e d t o t e r m i n a t e a command t h a t i n c l u d e s a numeric
o p t i o n . T h e r e s p o n s e t o t h e OS/8 * depends on t h e c a p a b i l i t y needed:
t h e format of t h e response i s d i s c u s s e d i n s e c t i o n s 4 . 0 ,

5 . 0 and 6 . 0

of t h i s manual.

3.1

Restart P r o c e d u r e

E P I C can be r e s t a r t e d a t l o c a t i o n 0 2 0 0 .

active ( r e f e r t o Section 4 . 2 ) .

D e f a u l t o p t i o n s remain

I f r e s t a r t i n g a f t e r h a v i n g used t h e

i s debefore r e s t a r t i n g

p a p e r t a p e o p t i o n , t h e Help message ( r e f e r t o s e c t i o n 7 . 0 )
stroyed.

Set bit

PI of t h e Switch R e g i s t e r t o

i n t h i s case, t o a v o i d any a r b i t r a r y o u t p u t .
4.0

PAPER TAPE FACILITY

The p a p e r t a p e o p t i o n

(/a) o f E P I C punches OS/8 f i l e s and f i l e

p a t c h e s o n t o p a p e r t a p e and creates OS/8 f i l e s from p a p e r t a p e s .
Whole f i l e s o r p a t c h e s ( b l o c k s ) of f i l e s c a n be r e a d o r punched. 2
P a r i t y checks a r e punched t o a s s u r e a c c u r a t e r e a d s .

Note t h a t a

unique p a p e r t a p e f o r m a t i s used s o t h a t t a p e s must b e b o t h punched
ahd r e a d by EPIC.

A f i l e . p u n c h e d by P I P , f o r example, i s n o t

acceptable t o EPIC.
4.1

Command Format

To r e q u e s t t h e p a p e r t a p e f a c i l i t y , t h e o p t i o n p must be s p e c i f i e d .
The form o f t h e r e s p o n s e t o t h e command d e c o d e r ’ s * ’ determines

whether a t a p e i s t o be punched o r r e a d .
files o r devices are s p e c i f i e d .
~

I n b o t h cases, no i n p u t
To punch a t a p e , t h e f i l e name is

_ _ _ _ ~

T e l e t y p e i s a r e g i s t e r e d trademark o f t h e T e l e t y p e C o r p o r a t i o n .
T h i s i s t h e method used t o s u p p l y l o n g p a t c h e s t o RTPS FORTRAN I V

users.
Throughout t h i s manual system o u t p u t i s i n d i c a t e d by underscoring.

specified; to read a tape, no file name is required (that information is encoded on the paper tape). The command line specifying
the mode of EPIC is terminated by ALTMODE.
To punch a tape, the response is:
*dev:name</g/other options$
To read a tape, the response is:
*dev:</$/other options$
If a file name is specified, EPIC looks up the name on the specified device and punches the file (includinu the file name) onto
paper tape. If no file name is specified, EPIC reads in a paper
tape and enters it onto the output device under the name it read in
from the tape.

The other options for handling paper tape are:
L

Use low speed paper tape reader or punch

Do not punch end of tape upon completion

Punch or read a patch (instead of the whole file)

Set relative block to g

Punch relative block n

Clear default name

These options can be combined to achieve the desired results.
Option:

If the /L option is not specified, EPIC assumes a
high-speed paper tape device. Thus, SYS:</$ means
read a tape from the high-speed reader to device
SYS but SYS:</B/L means read it from the low-speed
device.

E Option:

The /E option can be used to punch a series of
patches to a file for all patches except the last
one. With the /E option the end of tape m a r k is
not punched. The end of tape must have the
"end of tape" punch, a 3 7 7 punch and a length of
leader/trailer tape.

P Option:

The /P o p t i o n i s r e q u i r e d t o i n d i c a t e t h e t a p e t o be
r e a d o r punched i s a p a t c h , n o t an e n t i r e f i l e . Gene r a l l y , t h e command r e q u i r e d t o r e a d i n a p a t c h i s
simply dev:</P.
F i l e name and b l o c k s p e c i f i c a t i o n s
are a l r e a d y punched on t h e t a p e .
O p t i o n /Z o r =n must be used w i t h t h e /P o p t i o n t o
i n d i c a t e punching b l o c k
o r some o t h e r b l o c k ( r e l a t i v e block n ) , r e s p e c t i v e l y .
The p a t c h i s r e a d on
t o p of a n e x i s t i n g f i l e on t h e s p e c i f i e d o u t p u t dev i c e , i . e . , modifying an o l d f i l e , n o t c r e a t i n g a
new one.

Y Option:

The /Y o p t i o n i s used t o c l e a r t h e d e f a u l t f i l e name
when s w i t c h i n g from punching t o r e a d i n g p a p e r t a p e
and when r e a d i n g more t h a n one p a p e r t a p e .

4.2

Default Options

Throughout E P I C , i f o p t i o n s , f i l e s , o r d e v i c e s are n o t s p e c i f i e d ,
t h e program d e f a u l t s t o t h e l a s t s u c h i t e m s p e c i f i e d .
i n i t i a l d e f a u l t device:
specified.

There i s an

SYS i s assumed i f no o u t p u t d e v i c e i s

N o o p t i o n s are assumed i n i t i a l l y , however, e x c e p t f o r

r e l a t i v e b l o c k g.

Note t h a t d e v i c e and f i l e name o p t i o n s c a r r y

between E P I C modes la, 1 and 2 .

S p e c i f y i n g an o p t i o n ( i . e . , L , P ,

e t c . ) i n a command s t r i n g d i s a b l e s d e f a u l t t o any o p t i o n s
from t h e p r e v i o u s command ( e x c e p t fd, 1, 2 )

E , 2,

For example, t o punch b l o c k s

8 , 1 and 3% of t h e f i l e TRANS on t h e S Y S

d e v i c e and r e a d them back o n t o t h a t f i l e on DTA3, t h e commands a r e :

-.R E P I C

-*TRANS</P/E/Z$

Punch b l o c k g o f TRANS on highs p e e d punch w i t h no end of t a p e
punch.
Note t h a t E P I C d e f a u l t s t o
the paper-tape o p t i o n i n i t i a l l y
s o $J i s n o t r e q u i r e d i n t h i s c a s e .

-*=1>

Punch b l o c k 1 of f i l e TRANS w i t h
no end o f t a p e c h a r a c t e r on h i g h
speed device.

*= 3 P/P)

Punch block 30 of t h e f i l e TRANS
on high-speed punch. Punch end
of t a p e ( P d i s a b l e s E ) .

-*DTA3 :</YJ

Read t h e t a p e from t h e h i g h s p e e d
d e v i c e and p u t o u t t o f i l e whose
name i s encoded i n t h e p a t c h on
device DTA3 u n t i l end of t a p e i s
reached.
F i l e name and r e l a t i v e
b l o c k a r e punched on t h e t a p e so
t h i s i n f o r m a t i o n is n o t n e c e s s a r y .
Y clears t h e d e f a u l t name.(TRANS)

4.3

Error Conditions

If an error occurs while reading a block of paper tape, EPIC outputs
an appropriate error message (refer to Appendix A), and halts: the
user should reposition the paper tape to the leader/trailer just in
front of the block just read before continuing (refer to Appendix C);
three consecutive read errors terminate the command. When
EPIC is reading in a non patch file it checks the initial block read
of every tape and every block that is reread because of error to
determine if the read was accurate up to name and block number.
If
the wrong block number or file name is read, EPIC outputs an appropriate message indicating the type of error and halts with AC=7777
to allow the user to reposition the tape over the correct block or
enter the correct tape before continuinq.
4.4

Low Speed I/O

The execution of EPIC differs for low speed I/O. Before starting
a low speed punch EPIC halts with 7777 in the AC to allow the user
to turn on the low speed punch and then press the CONT key on the
computer console. Upon completion of a punch command EPIC halts
with the AC=% to allow the user to turn off the punch. When the
CONT key is pressed, EPIC recalls the command decoder. For low
speed input EPIC halts only upon completion of the read.

If a file or a series of files to be punched exceeds 32 blocks,
EPIC segments it by punching end of tape after 32 blocks. This
end of tape punch is done automatically and independently of the E
option; its purpose is to keep tapes physically short enough to
fit into a paper tape tray, Upon physical end of tape, EPIC halts
with the AC=a if the low speed punch is being used to allow the user
to turn off the punch before continuing. As soon as the punch is
turned off, EPIC outputs the message END OF TAPE ENTER NEXT and
then halts with the AC=7777 to allow both high and low speed users
to remove the paper tape. Note that low speed users get both halts,
but high speed users only get the 7777 halt. In general, a halt with
AC=% means turn paper tape device off and a halt with AC=7777 means
turn device on. All halts are terminated by depressing the console
CONTinue key. If EPIC encounters end of tape while reading a non-patch

f i l e it o u t p u t s t h e message END O F TAPE

ENTER NEXT and h a l t s w i t h

AC=7777 i n d i c a t i n g t h a t t h e f i l e i s segmented across a number of
t a p e s and t h a t t h e u s e r s h o u l d e n t e r t h e n e x t t a p e .
4.6

Device Codes

Most of t h e execute t i m e i s s p e n t w a i t i n g f o r p a p e r t a p e d e v i c e s .
During I / O w a i t , E P I C h o l d s t h e d e v i c e code and v e r s i o n number i n
t h e AC.
The d e v i c e code i s i n b i t s 3-5 and t h e v e r s i o n number i s
i n b i t s 6-11.
The codes are a s f o l l o w s
h i g h speed r e a d e r
h i g h s p e e d punch

l o w s p e e d r e a d e r ( c o n s o l e TTY)
low speed punch ( c o n s o l e TTY)
I f t h e u s e r f o r g e t s t o t u r n on t n e h i g n speed r e a d e r , EPIC hangs w i t n

l x x i n t h e AC.

E P I C can always be r e s t a r t e d a t

9.2916 ( r e f e r t o

The O S / 8 CTRL/C i s n o r m a l l y i n e f f e c t ; t h e e x c e p t i o n s
are when E P I C i s w a i t i n g f o r a p a p e r t a p e d e v i c e o r when i n p u t i s

Section 3.1).

from t h e low speed r e a d e r .
NOTE

When i n p u t i s from t h e low speed r e a d e r E P I C
f o r c e s t h e o u t p u t d e v i c e t o be SYS b e c a u s e i t
i s t h e o n l y OS/8 I / O h a n d l e r t h a t does n o t
check f o r CTRL/C.
Thus, i f t h e u s e r were t o e n t e r t h e command:
DTA2 :+/LJ
E P I C would f o r c e it t o be

SYS :+/L)

5.0

E D I T I N G CAPABILITY

Option 1 o f E P I C i s t h e f i l e e d i t i n g and s e a r c h i n g f a c i l i t y .
With t h i s f e a t u r e , p a t c h e s can b e added d i r e c t l y t o t h e f i l e by
s p e c i f y i n g r e l a t i v e b l o c k s and l o c a t i o n s i n t h e f i l e .

5.1

Initial Command Format

The general format of a command for the editing option is:

-. R EPIC)
*dev:name</options/l$
The/l$ specifies edit mode for EPIC.
As with the paper tape option, default conditions apply. If no
device and/or file name is specified, the last one mentioned is
used.
When editing, the only option available in the initial command is

Clear default name (if one exists)

Editing is performed one block at a time. The relative block currently being processed is the current block; the location currently
being processed is the current location ( d - 3 7 7 ) . Relative block
is the first block of the file if a file name is specified or block
of the device if no file name is specified.
5.2

Editing Commands

After the initial (file specification) command, a series of keyboard
commands are used to perform the editing. The general format of an
editing command is
X

x ,nl,n2
where x is a command letter and nl,n2 are octal numeric arguments.
If a numeric argument is used,the letter is followed by a comma. Up
to 3210 characters can be typed on a line. Default conditions apply
to these commands as well. If carriage return is the only character
typed as an editing command, the last command specified is executed.
The commands available are as follows:
E

Exit to command decoder; write out current block
of file if it has been modified.

R,n

Read r e l a t i v e b l o c k n ( o c t a l ) o f f i l e and set
c u r r e n t l o c a t i o n t o %. Do n o t w r i t e c u r r e n t
block.
I f n i s n o t s p e c i f i e d , t h e c u r r e n t block
i s r e a d . I f t h e r e l a t i v e b l o c k i s o u t o f range,
a ? i s p r i n t e d . T h e r e a r e 1341 b l o c k s p e r OS/8 t a p e
and 6 2 6 0 p e r RK8 d i s k p l a t t e r .

Write t h e c u r r e n t b l o c k of f i l e i f it h a s been
m o d i f i e d and r e a d i n t h e n e x t s e q u e n t i a l b l o c k
of t h e f i l e .
I f t h e c u r r e n t block i s t h e l a s t
b l o c k o f t h e f i l e , a ? i s p r i n t e d and t h e c u r r e n t l o c a t i o n i s unmodified.

S,nl,n2

Search t h e c u r r e n t block f o r t h e value n l w i t h
t h e mask n2.
I f e i t h e r n l o r n2 o r b o t h a r e
o m i t t e d , t h e l a s t v a l u e s p e c i f i e d i s used.
The
i n i t i a l mask i s 7777.
Masking i s performed i n a
l o g i c a l AND f a s h i o n .
I f t h e S command i s t e r m i n a t e d by t h e RETURN key t h e search i s f o r t h e
c u r r e n t block only.
I f t e r m i n a t e d by t h e LINE
FEED k e y , t h e s e a r c h c o n t i n u e s t o t h e e n d of t h e
file.
I f t h e search f a i l s ( e i t h e r i n t h e b l o c k
f o r a c a r r i a g e r e t u r n o r a t end o f f i l e f o r l i n e
f e e d ) E P I C p r i n t s a ?.
I f t h e search i s successf u l EPIC p r i n t s

m l m2
m3 /
where m l i s t h e r e l a t i v e b l o c k , m2 i s t h e r e l a t i v e
l o c a t i o n w i t h i n t h e b l o c k and m3 is t h e c o n t e n t s
of t h e l o c a t i o n . ( m l i s o m i t t e d if a p r e v i o u s match
w a s found i n t h e same b l o c k . ) To change t h e cont e n t s , t y p e t h e new c o n t e n t s ( o c t a l ) a f t e r t h e
slash.
T o c o n t i n u e t h e s e a r c h t y p e t h e LINE FEED
key: t o t e r m i n a t e t h e s e a r c h t y p e t h e RETURN key.
( I f t h e c o n t e n t s a r e n o t t o b e changed, t y p e o n e
of t h e t e r m i n a t o r s . )
O,n

Open l o c a t i o n n o f t h e c u r r e n t b l o c k .
If n is
n o t s p e c i f i e d , t h e l a s t opened l o c a t i o n i s t h e
d e f a u l t . I f t h e r e i s no d e f a u l t , l o c a t i o n JiIs
opened. E P I C r e s p o n d s w i t h
m1 /
which i s t h e c o n t e n t s of l o c a t i o n n.
T h i s location
may be m o d i f i e d a s i n s e a r c h . T e r m i n a t i n g w i t h
t h e LINE FEED key c l o s e s t h e c u r r e n t l o c a t i o n and
opens the next. If the current location is t h e
l a s t one i n t h e b l o c k , l o c a t i o n fl of t h e n e x t
b l o c k i s opened and t h e c u r r e n t b l o c k i s w r i t t e n
o u t a s i f it had been m o d i f i e d .

P r i n t c u r r e n t s t a t u s , as:

m l (F o r B) m 2 m 3 m4
where m l i s t h e c u r r e n t b l o c k , m2 i s t h e c u r r e n t
l o c a t i o n , m3 is t h e s e a r c h word and m 4 i s

the mask word. If F is typed, the file has
been modified since option 1 was requested;
B indicates,the current block has been modified.
Once a modified block has been written to the
file, the F is the only code output.
Thus a reasonable sequence is:

-.R EPIC

Call EPIC

*DSK: ISOMER</^$

Edit file ISOMER on DSK
Read block 2
S,3126,7778)
Search for a 312x in that block'
?
Not there.
+
Search for it throughout the file2
Found at block 4, location 110
8884 811%
3124 /312L)
Change contents to 3121
Search for 31xx throughout the
rest of the block (locations
,,7777
110-377)
$$p14 p1132
Found at location 132 of
block 4 .
3126 / 3127
Contains 3126. Change to 3127.
Check status
B 8132 3126 7777 At location 132 of block 4 which
has been modified; the current
search word is 3126 and mask is
7777.
Write block 4.
,w?
Block 4 written but file is only
four blocks long,no block 5 to read.
R,)
2
Read block 2
OJ%)
Open location 1%
1367 /1364+
Contains 1367. Change to 1364.
Check next location. No modifi-7)
cations.
Exit editing option.
E)

E, 2)

;d4

6.0

COMPARE CAPABILITY

A third feature of EPIC is file compare (/2). Because EPIC uses
an absolute location compare technique, there are no limitations
in the data format or length of the file.

6.1

Command Format

Option 2 of EPIC requires only one command, specified as:

I J F RETURN key
'-+ = LINE FEED key

The device and file name of one file to be compared is specified
to the left of the angle bracket, the device and file name of the
other to the right of the bracket. The options are:
A

Abort when the first non-match is found
List physical block number for each file where a
non-match exists

If no options are specified, the block numbers and locations of
each non-match are listed on the Teletype. Note that the initial
default device and file name to the right of the angle bracket
(input) are DTAB and block
of the input device, respectively.
For example, to compare files PYTHGl and PYTHG2 on 2 tapes and find
all unequal locations, the sequence can be as follows:

DTA1:0174

DTA2 0631
0152 7450 3421
0153 5741 2021
0154 3421 3022

To compare them and list unequal blocks the command is:

-*DTAl:PYTHGl<DTA2:PYTHG2/B/2$
If this block match followed the preceding locations match command,
a sufficient command and its results are:

-* /B)

DTAJ:0174

DTA2:0631

To abort after the first non-match, the sequence is:

*/A3

DTA1:0174

DTA2:0631

7.0

IIELP MESSAGE

The Help message reminds u s e r s f a m i l i a r w i t h E P I C of t h e o p t i o n s and
t h e i r notation.

T h i s message can be p r i n t e d on t h e T e l e t y p e when t h e

program i s c a l l e d and b e f o r e t h e command d e c o d e r ' s a s t e r i s k .
have t h e message p r i n t e d , b i t

of t h e c o n s o l e s w i t c h e s ( R i g h t

Switches f o r PDP-12 u s e r s ) m u s t be s e t t o 1.
by s e t t i n g b i t fl t o fl.

P r i n t i n g can be a b o r t e d

When t h e n e x t c a r r i a g e r e t u r n o c c u r s i n t h e

message, t h e message s t o p s and t h e command d e c o d e r ' s a s t e r i s k is
p r i n t e d . The command t o E P I C can t h e n be t y p e d .
The Help message i s :

When f a m i l i a r w i t h t h e o p t i o n s ( a f t e r r e a d i n g t h e rest of t h e
manual), a glance through t h i s l i s t should p i n p o i n t t h e o p t i o n s
r e q u i r e d f o r t h e EPIC job.

I n t h e message, PTAP r e f e r s t o t h e

p a p e r t a p e o p t i o n and FED t o f i l e e d i t i n g .

APPENDIX A
ERROR MESSAGES
EPIC can print one of the following error messages when performing
paper tape (option g) operations.
Message
BAD =BLK

Explanation
When EPIC is punching a patch it
checks the block specified by "=n"
to see if it is within range. If
the block is out of range EPIC outputs this error message and returnc
to the command decoder. For example if a file JOE were two blocks
long and the user requested:
JOE :+/P= 3

END OF TAPE

the error message would be printed.
EPIC was expecting a block of tape
and found end of tape instead.
EPIC halts with AC=7777 to allow
the user to reposition the tape.
When the user depresses CONTinue
E P I C attempts to read the block.

END OF TAPE ENTER NEXT

When EPIC is reading a file that is
segmented across a number of paper
tapes and encounters the end of a
segment,it outputs this message and
halts with AC=7777 to allow the
user to enter the next segment of
paper tape. Press the Console
CONT key to continue reading.

I/O ERROR

If EPIC encounters an error while
reading or writinq a mass storage
device, or a paper tape read fails
three consecutive times, it outputs
this error message, deletes the
output file if one exists, and
returns to the command decoder.

L/T ERROR

EPIC was expecting leader trailer
and found non-leader trailer while
attempting to read a block. The
program prints this error message
and halts with AC=7777 to allow
the user to reposition the tape
then press the Computer Console
CONT key.

A- 1

NEED:namel FOUND name2

EPIC

r e a d a b l o c k of t a p e f o r t h e

f i l e NAME2 when it was e x p e c t i n g a
b l o c k of t h e f i l e NAME1.
This
e r r o r would t y p i c a l l y o c c u r when a
u s e r comes t o t h e end of a segment
f o r NAME1 and e n t e r s some segment
of NAME2 i n s t e a d of t h e n e x t segment f o r NAME1. EPIC h a l t s w i t h
AC=7777 t o a l l o w t h e u s e r t o e n t e r
t h e c o r r e c t paper tape.
NEED:nlFOUND:n2

EPIC

PARITY ERROR

EPIC f a i l e d t o r e a d a b l o c k corr e c t l y , e . g . t h e r e a d e r dropped
some b i t s .
EPIC h a l t s with
AC=7777 t o a l l o w t h e u s e r t o repos i t i o n t h e t a p e so t h a t i t c a n
t r y t h e read again.

PTR:NAME

I S TOO B I G FOR dev:

r e a d b l o c k n2 of t h e f i l e when
i t w a s e x p e c t i n g b l o c k n l of t h e
f i l e . E P I C h a l t s w i t h AC=7777 t o
allow t h e u s e r t o r e p o s i t i o n t h e
paper tape.
This error typically
o c c u r s when t h e u s e r r e p o s i t i o n s
t h e t a p e t o t h e wrong b l o c k a f t e r
a read e r r o r .

The p a p e r t a p e f i l e NAME w i l l n o t

f i t on t h e s p e c i f i e d o u t p u t d e v i c e
E P I C a b o r t s t h e command
and r e t u r n s t o t h e command d e c o d e r .
E P I C makes t h e check f o r s i z e
b e f o r e w r i t i n g on t h e o u t p u t d e v i c e .
DEV:.

USR n dev:name

T h e USR e n c o u n t e r e d an e r r o r w h i l e
a t t e m p t i n g t o perform a f e t c h , l o o k u p ,
e n t e r , o r c l o s e on t h e f i l e NAME on
d e v i c e DEV.
n=l i s a f e t c h , n=2
i s lookup, n=3 is e n t e r , n=4 i s
close.
E P I C a b o r t s t h e command
and r e t u r n s t o t h e command d e c o d e r .
For example, i f t h e u s e r r e q u e s t s
E P I C t o punch a f i l e on SYS t h a t
does n o t e x i s t :

SYS :NILL+

E P I C o u t p u t s t h e message

USR 0002 SYS:NILL
i n d i c a t i n g t h a t it c o u l d n o t f i n d
t h e f i l e NILL on t h e d e v i c e SYS.

A- 2

APPENDIX B
LOADING RTPS FORTRAN I V FROM PAPER TAPE

For u s e r s who w i l l b e i n i t i a l l y l o a d i n g FORTRAN from p a p e r t a p e , t h e
p a p e r t a p e c a p a b i l i t y o f E P I C i s used.

The 1 0 f i l e s

F4. SV
PASS2 .SV
PASS 2 0 . S V
PASS3. SV

RALF SV
LOAD. S V
FORRTS FT
LIBRA. S V
EZGEN. SV
F O R I 0. SV

a r e on s e p a r a t e paper t a p e s and can be r e a d i n any o r d e r . A f t e r t h e y
have a l l been r e a d , t h e FORTRAN l i b r a r y , FORLIB, which i s 8 t a p e s
l o n g , m u s t be r e a d i n s e q u e n t i a l l y , as i n d i c a t e d by t h e number on
t h e l a b e l on each t a p e . The whole p r o c e d u r e i s :
. R EPIC)

*DTA1: < >

END O F TAPE ENTER NEXT
END O F TAPE ENTER NEXT
END O F TAPE ENTER NEXT
END O F TAPE ENTER NEXT
E N D O F TAPE ENTER NEXT
END O F TAPE ENTER NEXT
END O F TAPE ENTER NEXT
*+C

Call EPIC
Read 1 f i l e from h i g h s p e e d r e a d e r
t o DTA1.
I f RETURN o n l y is' t y p e d
SYS i s t h e d e f a u l t d e v i c e .
C l e a r d e f a u l t name, r e a d 2nd f i l e .
C l e a r d e f a u l t name, r e a d 3 r d f i l e .
Clear d e f a u l t name, r e a d 4 t h f i l e .
C l e a r d e f a u l t name, read 5 t h f i l e .
C l e a r d e f a u l t name, r e a d 6 t h f i l e .
C l e a r d e f a u l t name, r e a d 7 t h f i l e .
C l e a r d e f a u l t name, r e a d 8 t h f i l e .
C l e a r d e f a u l t name, r e a d 9 t h f i l e .
C l e a r d e f a u l t name, r e a d 1 0 t h f i l e .
Clear d e f a u l t name, r e a d f i r s t
l i b r a r y tape.
P u t 2nd t a p e i n p r i n t e r , p r e s s CONT.
P u t 3 r d t a p e i n p r i n t e r , p r e s s CONT.
P u t 4 t h t a p e i n p r i n t e r , p r e s s CONT.
P u t 5 t h t a p e i n p r i n t e r , p r e s s CONT.
P u t 6 t h t a p e i n p r i n t e r , press CONT.
P u t 7 t h t a p e i n p r i n t e r , p r e s s CONT.
P r e s s CONT.
Type CTRL/C t o r e t u r n t o t h e OS/8

Monitor.

A f t e r a l l 18 t a p e s have been r e a d s u c c e s s f u l l y , t h e e n t i r e FORTRAN
system i s on mass s t o r a g e .

B- 1

APPENDIX C
PAPER TAPE FORMAT

Paper tapes punched by EPIC have the following format:
7

FEET

IATA BLOCK

L/T

INCHES

L/T

DATA

8 INCHES......

BLOCK

L/T

.-.

2 FEET OF

HEADER

DATA
P

BYTE

DATA
P

BYTE

p
BYTE

C
..... ... .... DATA
P R
C
BYTE

C
R
C

Each byte is 1 2 punches (96 bits) and corresponds to 8 12 bit words;
each byte is followed by an even odd parity punch of the eight words
in the byte. Each block is terminated by two CRC punches of
longitudinal parity.
The header byte contains information about the file e.g., file name
and relative block number. The data bytes constitute the actual data
of the block; there are 3 2 data bytes per 2 5 6 word block.

c-1

APPENDIX D
LOADING E P I C FROM PAPER-TAPE

For u s e r s who r e c e i v e E P I C on p a p e r - t a p e ,

use t h e following

procedure t o l o a d t h e t a p e and s a v e it on a mass s t o r a g e d e v i c e .

-. R ABSLDR)
-*PTR: $TJ

U s e ABSLDR

-.SA SYS E P I C 8-7577;8288=8)

Save on mass s t o r a g e w i t h s t a r t i n g
a d d r e s s of 200

is outRead from r e a d e r ; a f t e r
p u t , t y p e any key t o s t a r t r e a d e r

D- 1

APPENDIX E
EPIC ASSEMBLY INSTRUCTIONS

The PAL/8 (version 7) assembler is used to assemble EPIC as follows:

-.R PAL83
*dev:EPIC.BNIdev:EPIC.LS<dev:EPIC.PA3

To create the save file, use ABSLDR:

-.R ABSLDR)
*dev:EPIC.BN$
-.SA dev EPIC 0-7577; $2$0=pl)

Call ABSLDR
Search for EPIC.BN on device specified
Save EPIC on device specified.
ff-7577 = area in core used during
execution.0200 = restart address

E- 1

APPENDIX F
E P I C INTERNAL DESCRIPTION

E P I C h a s h i s t o r i c a l r o o t s i n RTPS FORTRAN and i s an e x t e n s i o n o f a

program c a l l e d SHOP ( s h o r t form P I P ) whose purpose w a s t o f a c i l i t a t e
PIPing of t h e s t a n d a r d FORTRAN system programs.

SHOP a l l o w e d f i l e

t r a n s f e r s t o be performed w i t h a minimum amount of keyboard i n p u t .
The body of r o u t i n e s t h a t s u p p o r t e d SHOP p r o v i d e d t h e f o u n d a t i o n
f o r E P I C and t h e i n t e r n a l and e x t e r n a l c h a r a c t e r i s t i c s o f E P I C o r i g i n a t e from t h e b a s i c SHOP s u b r o u t i n e s . PTAP, FED, and COMPAR a l l
draw upon t h e s e r o u t i n e s .

The d e s c r i p t i o n t h a t f o l l o w s d i s c u s s e s

f i r s t t h e c e n t r a l r o u t i n e s and s e c o n d l y t h e c o n s t i t u e n t p a r t s o f E P I C .
1.0

CENTRAL ROUTINE

The r o u t i n e DECOD c a l l s t h e OS/8 command decoder and t r a n s l a t e s
i t s page 37 o u t p u t i n t o a format f o r u s e by t h e E P I C r o u t i n e s .
The
r o u t i n e SETDV i s c a l l e d t o f i l l t h e d e v i c e t a b l e s OUTTBL, and INTBL
w i t h t h e u n i t codes.
I f no o u t p u t o r i n p u t w a s s p e c i f i e d t h e res p e c t i v e t a b l e s a r e l e f t u n a l t e r e d i . e . , t h e l a s t s e t i s used.
The
r o u t i n e DODFN i s c a l l e d t o g e t t h e d e f a u l t f i l e name.
sets up t h e =n arguments checking f o r /H and / Z .
minated t h e i n p u t l i n e DECOD checks /n

DECOD a l s o

I f ALT MODE ter-

( d i g i t ) t o s e l e c t t h e new

mode, DECOD t h e n goes i n t o i t s s e l e c t e d mode c a l l i n g e i t h e r PTAP,
FED, o r COMPAR.
The E P I C r o u t i n e SWITCH i s c a l l e d t o i n t e r p r e t O S / 8 s w i t c h e s .
i n p u t i s a s t r i n g of O S / 8 s w i t c h a d d r e s s e s

Its

(17643-17645) and

s w i t c h f l a g s ; i t s o u t p u t i s s e t t i n g t h e f l a g s t o e i t h e r B o r -1 depending upon whether t h e u s e r t y p e d any a l p h a b e t i c (A-X)
t i o n s t o t h e command decoder.

s w i t c h op-

I f o n l y /H o r no s w i t c h e s were i n p u t

SWITCH does n o t p r o c e s s t h e t a b l e i . e . ,

the l a s t set of switches

s p e c i f i e d remain i n e f f e c t .
E P I C has a s e t o f r o u t i n e s t o f a c i l i t a t e TTY o u t p u t .

These a r e

TTOTXT, TYPNAM, OCTOUT, TYPDEV which o u t p u t a message i n s i x b i t

ASCII, t y p e an OS/8 f i l e name, t y p e a 1 2 b i t o c t a l d i g i t , and t y p e
a n O S / 8 d e v i c e name r e s p e c t i v e l y . The r o u t i n e DOUSR i s c a l l e d t o

F- 1

do a l l LOOKUPS, ENTERS, and CLOSES.
t o f e t c h an O S / 8 d e v i c e h a n d l e r .

The r o u t i n e GETHAN i s c a l l e d

The r o u t i n e s READ and WRITE a r e

c a l l e d t o r e a d from o r w r i t e on OS/8 mass s t o r a g e d e v i c e s .

2.0

PTAP

I f E P I C i s i n p a p e r t a p e mode t h e r o u t i n e PTAP i s c a l l e d PTAP i n t u r n
c a l l s t h e SWITCH r o u t i n e and t h e n l o o k s a t t h e name t o d e t e r m i n e
whether a f i l e i s t o be r e a d o r punched,
read.

no name i s i n t e r p r e t e d as

The b a s i c u n i t of a p a p e r t a p e f i l e i s c a l l e d a b y t e and

c o n s i s t s o f 1 2 frames o f d a t a f o l l o w e d by a p a r i t y frame.

The f o r -

mat of t h e p a p e r t a p e i s d i s c u s s e d i n Appendix C o f t h i s manual.
The p a p e r t a p e i n p u t r o u t i n e s r e a d one b y t e a t a t i m e and pack t h e
d a t a i n t o 1 2 b i t words u n t i l a 256 word b u f f e r i s f i l l e d whereupon
a block of d a t a i s w r i t t e n o u t .
reverse i.e.,

The punching p r o c e s s i s just t h e

a 256 word b l o c k o f d a t a i s unpacked i n t o a series

o f 1 2 frame b y t e s , and punched.

A f u l l b l o c k i s t r a n s f e r r e d by

c a l l i n g e i t h e r t h e r o u t i n e PREAD o r PWRITE.
T r a n s f e r s t o and from mass s t o r a g e d e v i c e s i s accomplished i n t h e
normal manner t h r o u g h OS/8

device handlers.

The r o u t i n e PREAD

s c a n s o v e r l e a d e r t r a i l e r u n t i l i t f i n d s a 2 8 1 punch i n d i c a t i n g
s t a r t of b l o c k : a f t e r which 33 b y t e s o f t a p e a r e r e a d i n .

The f i r s t

b y t e i s h e a d e r i n f o r m a t i o n and c o n t a i n s E P I C v e r s i o n number, f i l e
name, r e l a t i v e b l o c k , and f i l e l e n g t h i n t h a t o r d e r .
b y t e s contain t h e d a t a f o r t h e block.

The o t h e r 32

A p a r i t y frame accompanies

e a c h b y t e ; one b i t of p a r i t y f o r e a c h 1 2 b i t word i n t h e b y t e .

The

end of e a c h b l o c k c o n t a i n s two CRC words of l o n g i t u d i n a l p a r i t y .

PREAD

u s e s t h e r o u t i n e s GETBYT t o r e a d a b y t e of p a p e r t a p e ; PACK t o c o n v e r t
t h r e e 8 b i t frames i n t o two 1 2 b i t words; DOPAR t o compute b y t e
p a r i t y and DOCRC t o compute b l o c k p a r i t y .

The c u r r e n t v e r s i o n o f

E P I C has no e r r o r c o r r e c t i o n r o u t i n e s i . e . ,

i f an e r r o r o c c u r s i n

reading the only a l t e r n a t i v e is t o r e r e a d t h e block.

PWRITE

punches one b l o c k o f p a p e r t a p e and employs t h e r o u t i n e s PUTBYT,
DOPAR,

and DOCRC i n a manner a n a l o g o u s t o t h a t o f PREAD.

3.0

COMPAR

The COMPAR r o u t i n e i s f a i r l y s t r a i g h t f o r w s r d and o c c u p i e s one page
of core.

The r o u t i n e SWITCH i s c a l l e d t o s e t t h e s w i t c h o p t i o n

flags.

The s t a r t i n g b l o c k and l e n g t h a r e d e t e r m i n e d v i a page 37

F- 2

f i e l d 1 and t h e r o u t i n e DOUSR.

The r o u t i n e READ i s c a l l e d t o g e t

t h e d a t a and t h e n each word o f each f i l e i s compared.

I f a bad com-

p a r e i s e n c o u n t e r e d t h e r o u t i n e OCTOUT is c a l l e d t o o u t p u t b l o c k
numbers and d a t a words.

4.0

FED

Unlike o t h e r E P I C modes FED g e t s i t s own command i n p u t from t h e keyboard.

The r o u t i n e G I N P g e t s keyboard i n p u t and packs i t i n a 32

word b u f f e r (8 b i t A S C I I ) .

Character i n t e r p r e t i v e routines include

GETC ( g e t a c h a r a c t e r ) , GGBIT ( g e t a s t r i n g of 6 b i t A S C I I ) , and
GOCTAL ( g e t an o c t a l c o n s t a n t ) .

The l o c a t i o n s RBLK, CLOC, SRWD, and

MSKWD a r e r e s p e c t i v e l y t h e r e l a t i v e b l o c k number, c u r r e n t l o c a t i o n ,
s e a r c h and mask words: t h e s e arguments a r e used by t h e v a r i o u s rout i n e s . For example, i n t h e R command GOCTAL i s c a l l e d t o q e t a rel a t i v e b l o c k number.
I f no argument i s s p e c i f i e d , RBLK i t s e l f i s
used a s t h e "new" r e l a t i v e b l o c k number. Most of t h e commands a r e
s h o r t and f a i r l y s t r a i g h t forward.
The R , W, and E commands f o r i n s t a n c e t a k e up 56 l o c a t i o n s .

F-3

5.0

Flow C h a r t s

0
START

i n core

DECOD

Decoder
Setup I / O device
t a b l e s , =M,default

Set
new m n d e

+
No

G o t o CURNT mode

F-4

5.1

PTAP

options

block to
punch

F- 5

L
Read a

+
Punch a
block

Punch 3 7 7

Punch L/T

Halt

Type message

F- 6

0
Type block

words

F-7

5.2

PTIN

block
I

G e t name

l e n g t h of
file

E n t e r name

Check f o r
correct :
b l o c k and
name

F- 8

Write 1

block

Close f i l e

1 block

0
Type message

F-9

Yes

L
current

block

success

F-10

5.3

COMPAR

Q
COMPAR

G e t switch

options

G e t SBLK
and l e n g t h
of f i l e s

Read i n
next 2
blocks

Yes

0
DECOD

F-11

5.4

FED

.
4

rand
G e t SBLK I
length
of f i l e

INIT arguments

G e t KBRD

input

Get last

command

input

G e t new command

F-12

Q
'y"I
c u r r e n t block

Type F

Type

F-13

CURNT.
-f

BLK

new BLK

0
Return

calling
routine,

= new block

Read in
current
block
~~

Set CURNT. Lac. = P
Set CURNT. BLK not

modified

calling

F-14

Write
current
block

J
Set f i l e
modified

New block =
current

Clear
6 u r r e n t block
modified

u
calling

F-15

Q
current
block

0
DECOD

F-16

c>
Yes

current location +1

F-17

5.5

DOLOC

(2
DOLOC

location
and t y p e

Ret u r

word. S e t
block modi-

3
eturn

calling
outin

F-18

Q
I]

Match

F-19

Current l o c a t i o n =
C u r r e n t l o c a t i o n +1

Type ?

5
F-20

INDEX

Assembly i n s t r u c t i o n s , E - 1

Open l o c a t i o n i n c u r r e n t b l o c k ,
O p e r a t i n g mode, 1
Options, 1

Command f o r m a t , paper t a p e o p t i o n , 2
Commands, e d i t i n g , 7 , 8
Compare o p t i o n , 9 , 1 0
Current block, 7
Current location, 7

P o p t i o n (punch o r r e a d a p a t c h ) , 3
Paper t a p e f o r m a t , C - 1
Paper t a p e o p t i o n , 2 , 3
command f o r m a t , 2
Patch, t o read a, 3

Data block f o r m a t , C - 1
Default options, 4
Device c o d e s , 6

P h y s i c a l end of t a p e , 5
Print current status,
8
Punching c a p a b i l i t y , 3

E o p t i o n (do n o t punch end of
tape), #3
Editing capability, 6
E d i t i n g commands, 7

Editing option format,
Error conditions, 5
E r r o r messages, A - 1
End of t a p e , C - 1
n o t punched, 3
F i l e name,
2, 3
F i l e segmentation,

Read r e l a t i v e b l o c k ,
8
Restart procedure, 2
Search c u r r e n t b l o c k ,

1, 7

Tape (see p a p e r t a p e )
W r i t e current block,

Y o p t i o n (clear d e f a u l t name) , 3 , 7
5
Z o p t i o n (set r e l a t i v e block
to
I
3

Format
compare o p t i o n , 9
d a t a b l o c k , C-1
editing option, 7
paper t a p e o p t i o n , 2
FORTRAN f i l e e d i t i n g and s e a r c h ing, 6
Function d e t e r m i n a t i o n , 1
Hardware, 1
Help message, 11
High speed paper t a p e d e v i c e ,
I n p u t from low speed r e a d e r ,

L option,

3
Large f i l e s e g m e n t a t i o n ,
5
Leader t r a i l e r , C - 1
Loading
EPIC,
1, D-1
FORTRAN from p a p e r t a p e ,
B-1
Low-speed I/O, 5
Low-speed paper t a p e d e v i c e
option, 3
Low-speed r e a d e r i n p u t 6

Mode of o p e r a t i o n ,

=n o p t i o n (punch r e l a t i v e b l o c k n ) , 3

x -1

HOW TO OBTAIN SOFTWARE INFORMATION
Announcements for new and revised software, as well as programming notes,
software problems, and documentation corrections are published by Software
Information Service i n the following newsletters.
Digital Software News for the PDP-8 & PDP-12
Digital Software News for the PDP-II
Digital Software News for the PDP-9/15 Family
These newsletters contain information applicable to software available from
Digital's Program Library, Articles i n Digital Software News update the
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program to facilitate a complete investigation. An answer w i l l be sent to the
individual and appropriate topics of general interest w i l l be printed i n the
newsletter.
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please write to:

DECUS
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E P I C User's Manual

DEC-S8-UPTHA-B -D
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