Label Records Clarifications 1

[senthiljith]

Hi all

This is a Question regarding Label Records CLAUSE that is given in the Data Division. Can any one through light on this, why is this required ? when is this used ?

Thanks in advance

 

[MarcLodge]

Hi Senthiljith,
Label Records and similar clauses were covered here recently. Have a look at thread209-296943 and let us know if this is of any help.
Regards,
Marc Lodge

 

[senthiljith]

MarcLodge,

Thanks for the lots of info but i am still stuck up with Label records. I am across this in one of the books

"The LABEL RECORDS clause indicates the presence or absence of labels. If it is not specified for a file, label records for that file must conform to the system label specifications"

Do have any idea of what is the label that is being refered here.

Regards,
jith

 

[Dimandja]

Hi Senthiljith,

In the earlier days of computers (meaning mainframes), data files resided on devices that had to be constantly removed and installed. These devices included disks, tapes, 'drums', cards, perforated cards, etc...

This created a few problems. The operating system executed different I/O routines depending on which device was being referenced. Also, the possibility existed that data files on different devices could share the same name. Therefore another level of data file identification was needed: LABEL each device.

This technique of LABELing device still exists to this day. For example, insert a blank compact disc in your CD drive. Expand 'My Computer'. Your CD drive should simply say "CD Drive". Now insert, say, your COBOL installation disk in the CD drive. That drive should now display something other than just 'CD Drive'. That is your LABEL.

If this were an earlier computer, you wouldn't have the luxury of 'knowing' the drive letter (M that holds the disc; but, using the LABEL would find it for you.

Today, COBOL considers 'LABEL RECORD...' obsolete: you are advised to not use it in new applications. Modern computer architectures no longer support LABELing, they use disc drive names; and, besides, the trend for operating systems is to treat all devices in a consistent manner: the same I/O statements should work transparently the same way on any file residing on any device.

Dimandja

 

[senthiljith]

hi dimandja & marclodge

thanks for the lots of info. u have cleared my doubts