iAi)C3i5T Newoietter, Vol. d. No. i (Summer lyVB)

TKCHiUCAL STANUAHUS FOK MAGNETIC TAPE EXCHANGE

BETWEEN DATA ORGANIZATIONS

Karsten Boye Hasmussen

Danish Data Archives

INTKODUCTION TAPE LABELLING (NL, no label )

At the lASSIST-sessions in Upps- In principle, aii products t rom
aia August lY - 10, lyvo, there was tne major computer lirms should be
some discussion of the technical capable of reading ANSI labels
aspects of data exchange. In (American National Standard
recent years, the Danish Data labels). However, dilferent sys-
Archives (UUA) has had considerable terns may produce slightly dillerent
experience concerning exchange of ANSI-labels (due to frequent change
data files on magnetic tape -- ol operating systems) , and some
internationally between data organ- systems may not process ANSI labels
izations as well as inside Denmark correctly. bor these reasons, we
between computer installations would propose that all exchange
(notably IBM, CDC and UNIVAC). The tapes be written without labels
DA therefore accepted the invita- (NL, no label), as NL-tapes can
tion to write a note on these prob- delinitely be processed by any com-
lems proposing some usable stan- puter center. Leading tapemarks
dards. Although the DDA as a DO should be avoided.
(Data Orgnization) emphasizes the
importance ol documentation, this
note deals with the technical
aspects of data transfer on mag- THACKS ( 9-track , IbOU BPI , PE )

netic tape in general .

At most installations, 9-track
The correct procedure for tape drives are availaole; normally

exchange of magnetic tapes natur- this is true even tor computing
ally includes preparation ol a com- centers where the system uses
plete technical description of the /-track tape drives. At present,
tapes. However, the standards pro- the most commonly used density is
posed in this paper, while they may IbUU BPI (bits per inch) with phase
not always be the most effective encoded (PE) magnetization,
ones or the easiest ones to use,
should assure the possibility ot

reading the tape at other loca-
tions, even in cases where tne tape DATA KOHMAT ( blocked , fixed record
description for some reason is length , tfU char . , ASCII )

lacking. The philosophy behind the
standards is that of "simplica- Most system and/or machine
tion". You should never let a dependent files should be aban-
"data maniac" convince you to ship doned , as even a very good
a multi-reel, machine and operating
system dependent SPSS-file on seven
track tape; that is, unless you are
on really bad terms with the
receiver ol the file.

- Yb -



iA^SiST Newsletter, Vol. ^, No. i (Summer ly/b)

programmer would have to spend
months converting them to the local
tile tormat. Some installations
support conversion programs, but
these programs may not exist at the
receiving computer center, and even
If they do, the program 'level' may
De different. It is advisable to
snip data files in the most conser-
vative and simple format possible,
i.e. card image character format .

Given the tact that many computers
will have trouble handling large
blocks, the blocksize should not
exceed 204a bytes. Finally, we
would recommend using the ASCII
character set, which can normally
be converted by standard software
(or the operating system).

LUNLLUSIUN

For
file 1

the fo
istics
labels
the f

record
(ASCII
exceed
lation
plied
ported
readin
(In IS
Urgani
pleted
nation
zation
case

,

sent
capabl

exchange
n magnet
llowing
: the ta
(NL), y-

ile sho
s , be 1

; and h

ing 204a
s will h

by the m
by the c

g and con
fact IS r

zation H

by the m
al Federa
s) . Sho
tiles ot

only a m
e program

purposes
ic tape s

technical
pe should
track, 160
uld have
n charact
ave a bio
bytes. Mo
ave softw
anufac tur

e

omputing c

verting s

ellected i

egistry Fo
embers of
tion of Da
uld this
this Kind
inor prob
mer .

, a data
hould have
character-
be without

BPI, PE.
au byte

er tormat
cksize not
St instal-
are (sup-
r or sup-
enter) for
uch tiles,
n the Data
rm , com-
the Inter-
ta Urgani-
not be the
will pre-

lem to a

the file produced by WKITE ULt-
iNt-uj already tollow the standards
outlined above as tar as data for-
mat is concerned; and if, in the
future, a standard for documenta-
tion files is defined -- e.g. the
"data interchange tile" as proposed
by Hichard Koistacher -- the stan-
dard file will almost certainly be
in character card image format too.

hhb FKtNCtS

cue. UMS-IYU
VEHSION 1

No. bU^yt)
ICFSK. USIH

Arbor

:

Michigan

,

IBM OS UTILIT
tU. (GC

Nie, Norman,
FUITIUN.
Hill, lyy

Hoistacher

,

INTFHCHAN
2b>Y. Un
Febrauary

, Cl^BFR KECURD MANAGER
Reference Manual

,

YOO, I^Yb.
IS 111, VUL. 1. Ann

The University of
19Yb.

Its (ItBGKNER), IbTH
2B-bbbb-lt5; . April,

hi AL. SPSS StCUNU
New )(ork: McGraw-

Richard C. THE DATA
Gt h ILt. CAC doc. No

.

iversity of Illinois,
, lyya.

System supported software for gen -

erating and reading " standard "

files :

IBM: US UTILITIES (lEBGENER) Order
No. GC^'a-bbao- I 5 , Ibth ed .

April lyYj

CDC: DMS:1Y0, Cyber Record Manager
Version!, Reference Manual, No.
bU4yt)Y0U, lyYb

As mentioned above, this note
does not distinguish between data
and documentation files, as this
distinction is irrelevant for pur-
poses of generating and reading the
tape. Indeed, documentation files
trom the most commonly used pack-
ages (OSIRIS: the codebook; SPSS:

YY -