=;The OpenVMS Frequently Asked Questions (FAQ)D

The OpenVMS Frequently Asked Questions (FAQ)



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2.17.2 How many bytes are in a memory page?



HA memory page is the minimum unit of memory allocation in OpenVMS. With EOpenVMS VAX, the memory page size matches the disk block size: it is always 512 bytes.

GWith OpenVMS Alpha, the memory page size is variable, and it can range Efrom 8192 bytes (8 kilobytes) up to 64 kilobytes. The current system Gpage size can be determined using the sys$getsyi or f$getsyi PAGE_SIZE Eitem. Programs with hardcoded constants for the memory page size (or Apage alignment) should always assume a page size of 64 kilobytes.

DOn OpenVMS I64, the memory page size is also variable, ranging from H4096 bytes (4 kilobytes) up to 256 megabytes (MB) and potentially up to E4 gigabytes (GB). As with OpenVMS Alpha, sys$getsyi and f$getsyi and Gthe PAGE_SIZE itemcode can and should be used to determine the current Dsystem page size. In general, OpenVMS I64 will use a page size of 8 kilobytes, or larger.

BOn OpenVMS Alpha and on OpenVMS I64, a 512 byte area of memory--- Gequivalent in size to an OpenVMS VAX memory page---is often refered to as a "pagelet".U

2.17.3 How do I convert? Disk Blocks? KB, MB, GB, TB?



EThe smallest granularity of disk storage addressing is called a disk Eblock, or sometimes a disk sector. Groups of disk blocks are usually Aorganized together into the smallest unit of storage that can be Hallocated, and this unit is called a disk cluster. The number of blocks Ein a cluster is the cluster factor, and is established when the disk volume is initialized.

DEach individual disk block is composed of five hundred twelve (512) Ebytes, or one-half kilobyte. Each byte is comprised of eight bits. A Fbit represents the smallest unit of information, typically refered to as a one or a zero.

EOpenVMS tends to uses base two notation for disk storage, while disk ?storage capacity specifications from most storage vendors will generally use base ten notation.

FAn OpenVMS disk block is 512 bytes in size; this is one-half kilobyte in base two notation.

DThe following table describes the prefix, the abbreviation, and the Fassociated base ten (as used by marketing and by storage vendors) and >base two (OpenVMS and various other operating systems) values.

 

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6          Base Ten                           Base Two G          --------------------------------   ------------------------- GKilobyte  (KB)  10**3                 1000   2**10                1024 GMegabyte  (MB)  10**6              1000000   2**20             1048576 GGigabyte  (GB)  10**9           1000000000   2**30          1073741824 GTerabyte  (TB)  10**12       1000000000000   2**40       1099511627776 GPetabyte  (PB)  10**15    1000000000000000   2**50    1125899906842624 GExabyte   (EB)  10**18 1000000000000000000   2**60 1152921504606846976 




GThe base ten representation of the 2**40 value is 1099511627776, which Fis obviously rather ugly. When viewed as a base eight or base sixteen D(octal or hexadecimal, respectively) value, the value is far nicer. HSpecifically, the value is 10000000000 and 40000000 when represented in $octal and hexadecimal, respectively.



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FAQ 6 Notation

EWithin the OpenVMS FAQ, a thousand bits (either assuming base two or :base ten, as determined by the context) is refered to as aD kilobit, and is always represented by the appreviation Kb, while a " thousand bytes is refered to as aI kilobyte and is always abbreviated as KB. Similar notational usage also holds for Megabits (Mb) and9 Megabytes (MB), and for the various other units.


HOpenVMS operating system references to system and storage are generally @to the base-two version (eg: 1024, in the case of a kilobyte or Gkilobit) while storage hardware references and hardware specifications 1are generally to the base-ten version (eg: 1000).

ATo convert OpenVMS disk blocks to (base two) kilobytes (KB; 1024 >bytes), simply divide by two. To convert blocks to (base two) Gmegabytes, divide by 2048. Blocks to (base two) gigabytes (GB), divide Cby 2097152. These particular divisions can also be performed using Fbitshifts: to divide a value by two, shift the binary value rightward by one bit position.

BTo convert OpenVMS disk blocks to (base ten) kilobytes, divide by approximately 1.953125.

GFor those folks with an interest in odd applications for prefixes, and Cparticularly for those folks also rummaging around deep within the *OpenVMS operating system, a microfortnight is approximately one second.


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Chapter 3
Documentation


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If you are searching for something here, please (consider using the text-format FAQ.

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3.1 Where can I find online copies of OpenVMS manuals?



CThe HP OpenVMS and HP Layered Product documentation is copyrighted material.

GHTML format on-line product documentation sets for specific HP OpenVMS $products are presently available at:



HDocumentation is offered on separately orderable CD-ROM media through a Hsubscription to the Consolidated On-Line Documentation (ConOLD) product j(see Section 2.6.) ConOLD manuals are readable with BNU, a viewer that Gis supplied with the documentation distribution. BNU can display HTML, /Bookreader, and documentation in other formats.

FMGBOOK, a viewer for Bookreader-format documentation is available for Ccharacter-cell terminals (eg. VTxxx) via the WKU VMS Freeware file Tserver -- see question Section 13.1 for details.

GInformation on the XPDF DECwindows PDF viewer for OpenVMS is available ein Section 13.1, and XPDF kits are available on various Freeware Gdistributions. An alternative on OpenVMS Alpha uses the Adobe Java PDF Eviewer, though this viewer is generally considered to be both slower =and more resource-intensive when compared to the XPDF viewer.m

3.2 What online information and websites are available?



AOn your OpenVMS system, the HELP command can provide a wealth of Cinformation, not only on DCL commands but on system services (HELP HSystem_Services) and Run-Time Library routines (HELP RTL_Routines). The >introduction displayed when you type the HELP command with no .additional keywords provides further pointers.

POpenVMS Marketing runs a web server at #http://www.hp.com/go/openvms/ 

Here, you will find product information, strategy documents, product roadmaps, the contents of the latest OpenVMS Freeware CD-ROM and more.

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Table 3-1 OpenVMS Websites
URL Sponsor
 HP OpenVMS Marketing
  L http://www.hp.com/go/openvms/
 Encompass DFWCUG
  1 % http://www.openvmshobbyist.org/
 Arne Vajhøj
  J http://www.levitte.org/~ava/
 Saiga Systems
  < http://www.saiga.com/
 Wayne Sewell
  D http://www.tachysoft.com/
 proGIS Software
  2 & http://www.progis.de/openvms.htm
 Jeff Cameron
  J http://www.jcameron.com/vms/
> David Mathog's (quite useful) information about OpenVMS.
  : . http://saf.bio.caltech.edu/soft_doc.html
 Cracking
 "The Beave"K
Includes system cracking information that can be of interest to M OpenVMS System Managers, and to OpenVMS Network and Security Managers. < This information is available at the Deathrow cluster.
  @ 4 http://manson.vistech.net/ht_root/Hack-VMS-faq
, Undocumented Features
 DECUS Deutschland
  F : http://zinser.no-ip.info/www/eng/vms/qaa/undoc.htmlx
 Arne Vajhøj
  ; / http://www.levitte.org/~ava/vms_tip.htmlx
N The OpenVMS Freeware contains various examples of undocumented features  and interfaces
  8 , http://www.hp.com/go/openvms/freeware/
C Comparisons of UNIX and Linux shell commands and DCL Commands
  E 9 http://www.mcsr.olemiss.edu/unixhelp/VMStoUNIX.html
  J > http://wwwvms.mppmu.mpg.de/vmsdoc/UNIX_VMS_CMD_XREF.HTML
; Comparisons of emacs and OpenVMS text editor commands
  D http://www.unh.edu/cis/docs/vms-to-unix/Emacs/cheat-sheet.html
% Bibliographies
  = 1 http://www.openvms.org/pages.php?page=Books
  < 0 http://www.levitte.org/~ava/vms_book.htmlx
# Introductory
  r Please see Table 3-2 for listings of introductory web sites and  related materials.
" Programming
An OpenVMS Programming FAQ
  F http://www.pdv-systeme.de/users/martinv/VMS_Programming_FAQ.html
! Networking
J Tutorial information and tips for connecting OpenVMS systems to the  Internet
  1 % http://www.tmesis.com/internet/
C Documentation and Specifications for DECnet Phase IV, DECnet 6 task-to-task DCL examples, and a whole lot more.
  6 * http://www.hp.com/go/openvms/wizard/
/ HP OpenVMS Documentation
  s Please see Table 3-2 for listings of documentation web sites and  related materials.
) System Performance
  < See Section 14.2.
' Patch (ECO) Kits
  I For the HP Services FTP server hosting Various contract-access and j non-contract access ECO (patch) kits, see section Section 5.17.
+ Catalogs and Pricing
3 HP Product QuickSpecs and product information
  7 + http://www.hp.com/go/productbulletin/
6 The HP Systems and Options Catalog (SOC) archive
  http://www.compaq.com/products/4
quickspecs/soc_archives/SOC_Archives.html
5 Hardware and Software Archives
A The VAXarchive, including hardware and software information
  6 * http://vax.sevensages.org/index.html
" A VAX to Alpha upgrade diary
  H < http://www3.sympatico.ca/n.rieck/docs/alpha_diary.html
9 Scanned versions of old DIGITAL manuals from DFWCUG
  < 0 http://www.montagar.com/~patj/dec/hcps.htm
B A wide variety of HP VAX, Alpha, platform and other product 7 documentation. Some introductory, some technical.
  G ; http://www.compaq.com/support/techpubs/qrg/index.html
! dtrwiz's Datatrieve website
  N http://dtrwiz.home.netcom.com/
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3.3 How do I extract the contents of a HELP topic to a text file?



FTo extract all the text of a HELP topic (and its subtopics) to a text Afile for perusal with a text editor, printing out, etc., use the following command:

 

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3$ HELP/OUT=filename.txt help-topic [help-subtopic] 




CIf the help text you want is not in the standard help library (for Dexample, it's help for a utility such as MAIL that has its own help Hlibrary), add /LIBRARY=libname after the HELP verb. To see the names of 5help library files, do a directory of SYS$HELP:*.HLB.h

3.4 Does OpenVMS Marketing have an e-mail address?



HYes - if you can't get the answers to marketing questions elsewhere, if <you have comments or complaints about OpenVMS, send mail to Copenvms-info{atsign}hp.com. This address is not a support >channel, and is solely intended to provide informal method to 7communicate directly with members of OpenVMS Marketing.o

3.5 Where can I learn about OpenVMS executive internals?



HThe OpenVMS Internals and Data Structure manual (IDSM) explains how the FOpenVMS executive works. The book covers the operating system kernel: Bprocess management; memory management; the I/O subsystem; and the Hmechanisms that transfer control to, from, and among these. It gives an Foverview of a particular area of the system, followed by descriptions Dof the data structures related to that area and details of the code that implements the area.

HThe first edition of the OpenVMS Alpha internals book describes Version F1.5. Although there have been several releases of OpenVMS Alpha since GVersion 1.5 (V6.1, V6.2, V7.0, V7.1, etc) and many details in the book Dare no longer accurate, it continues to provide a strong conceptual !description of OpenVMS internals.

>This book has been split into five pieces, each to be updated @separately. The first such volume, published in early 1997, was E"OpenVMS Alpha Internals and Data Structures: Scheduling and Process >Control," which covers the Version 7.0 implementation of true ;multithreading and the changed scheduling model it implies.

=The internals books are available through Digital Press, see /Section 3.6w

3.6 Where can new users find tutorial information about OpenVMS?



GFirst, see if your local site has information on this topic. Each site Hcan have site-specific features and configuration. Some sites will have Gsite-specific new user's documentation, covering various site-specific @things that are difficult or impossible for the general OpenVMS documentation to cover.7

3.6.1 Tutorial Websites?



Various websites with OpenVMS information are available; Table 3-2 contains some suggested URLs.

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Table 3-2 OpenVMS Tutorial and Documentation Websites
URL Sponsor
# Introductory
; / http://www.levitte.org/~ava/vms_faq.htmlx
; / http://saf.bio.caltech.edu/vms_sheet.html
J > http://seqaxp.bio.caltech.edu/www/vms_beginners_faq.html
  $ Various introductory materials
8 , http://www.montagar.com/openvms_class/
  M Members of the Encompass DFWCUG maintain a website with many materials N available, including an Overview of OpenVMS, an Introduction to DCL and K the TPU Editor, Advanced DCL Command Procedures, OpenVMS Operations: L Batch, Print, Tape, an Introduction to OpenVMS Management, to OpenVMS M User Management, to OpenVMS Network Management, and to OpenVMS Cluster J Management. These training materials have been presented at various  DECUS symposia.
E 9 http://www.mcsr.olemiss.edu/unixhelp/VMStoUNIX.html
  I A comparison table of various command-level tasks, with information % % % N on the UNIX and Linux shell command(s), and on the OpenVMS DCL  command(s).
/ HP OpenVMS Documentation
3 ' http://www.hp.com/go/openvms/doc/
  G Various introductory guides as well as more advanced manuals are E available in the OpenVMS and layered product documentation set.
* HP OpenVMS Training
: . http://www.compaq.com/training/home.html 
> 2 http://www.openvms.compaq.com/wbt/index.html
  L HP offers training information and Technical Resource Kits (TRKs) and M other Training for OpenVMS. An OpenVMS certification (testing) program  is also available.
J http://www.jcameron.com/vms/
   An OpenVMS Quiz
B http://www.CCSScorp.com/
  > CCSS Interactive Learning has OpenVMS training materials
B http://www.acersoft.com/
  ? AcerSoft Training information, and Shannon Knows Punditry
> http://www.mindiq.com/
  ! MindIQ training information
D http://www.quadratrix.be/
  K Quadratrix; OpenVMS training, products and services; affiliated with ! Global Knowledge and KeyJob





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