HP OpenVMS Systems

Ask the Wizard

HP OpenVMS Systems

OpenVMS information

» What's new on our site
» Upcoming events
» Configuration and buying assistance
» Send us your comments

HP OpenVMS systems

» OpenVMS software
» Supported Servers
» OpenVMS virtualization
» OpenVMS solutions and partners
» OpenVMS success stories
» OpenVMS service and support
» OpenVMS resources and information
» OpenVMS documentation
» Education and training

Quick Links

» Non-javascript page
» Ask the Wizard

Test Drive OpenVMS

» OpenVMS I64 test drive
» Java test drive

Other information resources available to you include:

» OpenVMS freeware
» ECO kits, software and hardware support, prior version support
» Alpha SRM, ARC, and AlphaBIOS firmware updates
» ENCOMPASS - HP user group
» OpenVMS software downloads, OpenVMS freeware CD-ROM
» OpenVMS firmware locations
» DECconnect passive adaptor charts
» Cables reference guide
» MicroVAX console commands
» OpenVMS student research

Select a topic below to see Questions Frequently Asked by partners

» Using the online documentation library(installing BNU from the asap SDK)
» Global sections(how to create and use.)
» xx$CREATE_BUFOBJ system service(usage)
» Ethernet address(methods of determination)
» Shareable images(cookbook approach to creating one)
» Sharing data/code at absolute addresses(a guide with examples)
» Determining the Alpha microprocessor
» Using GETSYI to get hardware status

Evolving business value

» Business Systems Evolution
» AlphaServer systems transition planning
» Alpha RetainTrust program

Related links

» HP Integrity servers
» HP Alpha systems
» HP storage
» HP software
» HP products and services
» HP solutions
» HP support
disaster proof
HP Integrity server animation
HP Integrity server animation
Content starts here

Ask the Wizard Questions

time limit of 10000 days?

The Question is:

Dear Wizard, In an application, we are using a unique
number to describe a manufactured product.  This number
is the number of seconds since a defined base
time (Jan 1, 1975).  As the year 2000 approaches, I began
investigating to ensure that this unique number algorithm
would still be valid.  The method we are using to
determine this number is to call SYS$GETTIM() to get the
current time in 64-bit format.  Next call SYS$BINTIM()
to convert the ASCII base time to 64-bit format.  Then we
call LIB$SUB_TIMES() to calculate the resultant delta
time ... this is the unique number.  This works great and
would continue to work except for one problem.  The
resultant delta time calculated using LIB$SUB_TIMES() must
be less than 10,000 days.  Why is this limitation there?
If the delta resultant time is an unsigned quadword
shouldn't it be able to represent 1.8 times 10 to the 19
power seconds?  Is there a graceful way to resolve this

The Answer is:

The restriction was most likely imposed because the display form of a delta
time has a four digit number-of-days field.  You could consider using
LIB$SUBX instead.  On an Alpha, you can do the subtraction directly in the
language of your choice.