Subject: Aegis Frequently Asked Questions (FAQ)
From: Peter Miller <millerp@canb.auug.org.au>
Newsgroups: comp.software-eng,comp.software.config-mgmt,
        comp.software.testing,comp.sources.d,alt.sources.d

Submitted-by: Peter Miller <millerp@canb.auug.org.au>
Archive-name: aegis.4.24.3/FAQ

This message contains answers to a number of frequently asked
questions about Aegis.  If you don't know what Aegis is, read on.

Suggestions for additions or improvements to this FAQ are most
welcome.


                               Contents
1.   What is Aegis?
1.1.   What operating systems are supported?
1.1.1.   Cygwin
1.1.2.   Windows NT
1.2.   Where can I get Aegis?
1.3.   Is Aegis actively being maintained?
1.4.   Is there an Aegis mailing list?
1.5.   How does Aegis compare with program X?
2.   Configuration and initial build problems
2.1.   Changing Makefile and common/config.h
2.2.   RCS
2.3.   SCCS
3.   Testing
3.1.   Can I use something besides a shell script?
3.2.   Testing curses programs
3.2.1.   Expect
3.3.   Testing X11 programs
3.3.1.   replayXt
3.4.   Testing embedded systems
3.5.   Do I really need to test my software?
4.   Miscellaneous
4.1.   How do you pronounce "Aegis"?
4.2.   How do I automate the integration queue?
4.3.   How do I enforce coding standards?
4.4.   How do I get dates printed before and after build commands?
4.5.   How do I stop Aegis automatically merging?
4.6.   How do I modify which developer is assigned to a change?
4.7.   Do I have to type all the configuration examples in the User Guide?
4.8.   Is there a way to recreate a previous baseline?
4.9.   How do I stop it using the pager?
4.10.   Why does develop end complain about builds?
4.10.1.   Build Time Stamps
4.10.2.   Build Architectures
5.   Internationalization
5.1.   Say What?
5.2.   So why are the error messages So Bad, now?
5.3.   What controls which language is used?
5.4.   What localizations are available?
5.5.   So can I change the text of error messages?
6.   Branches
6.1.   What is a Branch?
6.2.   What is an Anabranch?
6.3.   Do branches have to end?
6.4.   Why are branches called projects?
6.5.   Why must aed be used when integrating a branch?
6.6.   How come the branch baseline is incomplete?

----------------------------------------------------------------------

Subject: 1.  What is Aegis?

Aegis is a transaction-based software configuration management system.
It provides a framework within which a team of developers may work on
many changes to a program independently, and Aegis coordinates
integrating these changes back into the master source of the program,
with as little disruption as possible.

For a more complete description, see the README file or the User
Guide.  Both are available from the anonymous FTP site (see below).

------------------------------

Subject: 1.1.  What operating systems are supported?

Aegis will run on almost any version of UNIX.  The distribution
contains a configure script generate by GNU autoconf to adapt to your
site.

There is no Aegis port to NT, OS/2, MS-DOS or VMS.  The author has no
expertise is these operating systems.  If you do have such expertise,
you are welcome to donate a port of Aegis, and I will try to include
your work in the next release.

------------------------------

Subject: 1.1.1.  Cygwin

There is a very capable UNIX emulation layer known as Cygwin available
from Cygnus.  Please see http://sourceware.cygnus.com/cygwin/ for more
information.  But before you get too excited, see the next item.

------------------------------

Subject: 1.1.2.  Windows NT

Aegis depends on the underlying security provided by the operating
system (rather than re-invent yet another security mechanism).
However, in order to do this, Aegis uses the POSIX _s_e_t_e_u_i_d system
call, which has no direct equivalent on Windows NT.  This makes
porting difficult.  Single-user ports are possible (_e_._g_. using
Cygwin), but are not usually what folks want.

Compounding this is the fact that many sites want to develop their
software for both Unix and Windows NT simultaneously.  This means that
the security of the repository needs to be guaranteed to be handled in
the same way by both operating systems, otherwise one can act as a
"back door" into the repository.  Many sites do not have the same
users and permissions (sourced from the same network register of
users) on both Unix and Windows NT, making the mapping almost
impossible even if the security models did actually correspond.

Most sites using Aegis and Windows NT together do so by running Aegis
on the Unix systems, but building and testing on the NT systems.  The
work areas and repository are accessed via Samba or NFS.

------------------------------

Subject: 1.2.  Where can I get Aegis?

Aegis is available by WWW from
    URL:    http://aegis.sourceforge.net/
    File:   aegis.4.24.3.README   # the README file from the tar set
    File:   aegis.4.24.3.faq      # Frequently Asked Questions
    File:   aegis.4.24.3.lsm      # description in LSM format
    File:   aegis.4.24.3.rm.pdf   # PDF of the Reference Manual

    File:   aegis.4.24.3.tar.gz   # the complete source
    File:   aegis.4.24.3.ug.pdf   # PDF of the User Guide

------------------------------

Subject: 1.3.  Is Aegis actively being maintained?

Yes, Aegis is actively being maintained by the author.  You can
contact him by email
               Peter Miller <millerp@canb.auug.org.au>

------------------------------

Subject: 1.4.  Is there an Aegis mailing list?

Yes.  Discussion may include, but is not limited to: bugs,
enhancements, and applications.  The list is not moderated.

The address of the mailing list is
        aegis-users@canb.auug.org.au

DO NOT send email to the list if you wish to subscribe.

To subscribe to this mailing list, send an email message to
majordomo@canb.auug.org.au with a message body containing the single
line
        subscribe aegis-users
If you have an address which is not readily derived from your mail
headers (majordomo is only a Perl program, after all) you will need to
use a message of the form:
        subscribe aegis-users _a_d_d_r_e_s_s
where _a_d_d_r_e_s_s is an email address to which you want messages sent.

The mailing list is archived at eGroups.  The URL is
http://www.egroups.com/list/aegis-users/info.html and then follow the
links.

The software which handles this mailing list CANNOT send you a copy of
_A_e_g_i_s.  Please use FTP or ftp-by-email, instead.

------------------------------

Subject: 1.5.  How does Aegis compare with program X?

For all X, "The author has no experience with X.  If you wish to
contribute a comparison between Aegis and X, it will be considered for
addition here."

------------------------------

Subject: 2.  Configuration and initial build problems

Aegis is accompanied by a set of regression tests, and the BUILDING
instructions included in the distribution detail how to run these
tests.

------------------------------

Subject: 2.1.  Changing Makefile and common/config.h

It is a Bad Idea to change the Makefile or the common/config.h file by
hand.  This is because much of the work done by the configure script
is inter-related.

In particular, if you change the C compiler (CC) you absolutely must
do this with the involvement of the configure script.

------------------------------

Subject: 2.2.  RCS

The tests distributed with Aegis use RCS as their history tool.  It is
important that you use version 5.6 or later.

There seems to be a problem with the version of RCS distributed with
HP/UX, even though it claims to be RCS-5.6.0.1.  You will need to get
the latest GNU RCS if you are on a HP box.

------------------------------

Subject: 2.3.  SCCS

The tests do not automatically detect that you have SCCS.  You will
need to go out and grab RCS even if you already have SCCS installed at
your site.

------------------------------

Subject: 3.  Testing

One of the things many sites like about Aegis, is that it provides
mandatory testing.  This enforcement of testing is optional, and is
configurable per-project.

Please note that even if Aegis' testing framework is not useful to
your project, the other aspects of Aegis' process still are (e.g.
concurrent development, mandatory reviews, etc.).

------------------------------

Subject: 3.1.  Can I use something besides a shell script?

Yes, the "test_command" field of the project configuration file may be
set to whatever command you like, see _a_e_p_c_o_n_f(5) for more information.

A shell script is the default, because you can run anything out of the
shell script.  In particular, you can set up a temporary directory
within which to run the tests.  If you "cd" into this temporary
directory when running tests, cleanup, no matter what the fallout,
even a core dump, is thus a simple matter of "rm -rf" of the temporary
directory.

------------------------------

Subject: 3.2.  Testing curses programs

I don't have a curses program tester, nor do I know of one.  It seems
to me that the "screen" program contains all the necessary elements,
however additional code would be required to make it a suitable test
harness.

If anyone has found suitable curses testers, even commercial ones, I
would be happy to list (FTP) locations here.

------------------------------

Subject: 3.2.1.  Expect

Some sites have been using "expect" to test curses programs.  You need
to be careful about terminal types.  The author is Don Libes
<libes@nist.gov>

expect is available by anonymous FTP from
    Host:   sunsite.unc.edu
    Dir:    pub/Linux/system/Shells
    File:   expect-5.12.tgz

The author has not personally used this system, and so can make no
comment on it.

------------------------------

Subject: 3.3.  Testing X11 programs

I don't have an X11 program tester, however several commercial ones
seem to be advertised heavily.

If anyone has found suitable X11 testers, even commercial ones, I
would be happy to list additional (FTP) locations here.

------------------------------

Subject: 3.3.1.  replayXt

ReplayXt is a library that allows Intrinsics (or Xt) based application
to be executed from a script file.  In particular, applications based
on the Athena and the Motif toolkits can be played.  The author is Jan
Newmarch <jan@pandonia.canberra.edu.au>

replayXt is available by anonymous FTP from
    Host:   ftp.x.org
    Dir:    /contrib/devel_tools
    File:   replayXt.README
    File:   replayXt.1.1.tar.z

The author has not personally used this system, and so can make no
comment on it.  This entry originated from Simon Pickup
<simon@adacel.com.au>

------------------------------

Subject: 3.4.  Testing embedded systems

Yes, embedded system can be developed with Aegis.  Naturally, you will
need a suitable cross compiler.

To test embedded software, you will need suitable testing hardware:

1. you will need to be able to (automatically) download the software
into suitable hardware - probably with RAM emulating the ROM of the
distributed product.

2. you will need to be able to simulate the various inputs and capture
the various outputs, if you don't want to do manual testing.

3. you will probably have to write the testing program yourself, to
allow scripting the inputs and outputs.

4. The gotcha is that in diverting input and output, you will need to
manually test the device drivers, because the tests will probably not
exercise them.

The author has worked in an environment like this, and Aegis is
definitely intended to be useful in this situation.

------------------------------

Subject: 3.5.  Do I really need to test my software?

No, you do not.  There are alternatives, as this quote demonstrates:

    New York, NJ, Sept. 24 -- People for the Ethical Treatment of
    Software (PETS) announced today that seven more software companies
    have been added to the group's "watch list" of companies that
    regularly practice software testing.

    "There is no need for software to be mistreated in this way so
    that companies like these can market new products," said Ken
    Granola, spokesperson for PETS.  "Alternative methods of testing
    these products are available."

    According to PETS, these companies force software to undergo
    lengthly and arduous tests, often without rest for hours or days
    at a time.  Employees are assigned to "break" the software by any
    means necessary, and inside sources report that they often joke
    about "torturing" the software.

    "It's no joke," said Granola.  "Innocent programs, from the day
    they are compiled, are cooped up in tiny rooms and 'crashed' for
    hours on end.  They spend their whole lives on dirty, ill-
    maintained computers, and are unceremoniously deleted when they're
    not needed anymore."

    Granola said the software is kept in unsanitary conditions and is
    infested with bugs.

    "We know alternatives to this horror exist," he said, citing
    industry giant Microsoft Corp. as a company that has become
    extremely successful without resorting to software testing.

If anyone has an accurate attribution for the above quote, I would
like to include it here.

------------------------------

Subject: 4.  Miscellaneous

This section contains a whole bunch of things which do not yet belong
anywhere else.

------------------------------

Subject: 4.1.  How do you pronounce "Aegis"?

There are many alternatives for pronouncing this word, and all focus
on the myriad of sounds available for the "ae" vowel.  Alternatives
include: maestro, aerial, algae, etc.  The author has chosen the
pronunciation found in the majority of dictionaries: ee.j.iz.  That is
"ee" as in "tree", a "j" as in "job", and "iz" as in "prism".

------------------------------

Subject: 4.2.  How do I automate the integration queue?

There is a Perl script distributed with Aegis called _a_e_i_n_t_e_g_r_a_t_q(1)
which can be run from _c_r_o_n(1) daily, or whatever.  This Perl script is
a good starting point for customizing automatic integrations.

Please note that the integration phase also serves to answer the
question "who reviews the reviewers?"  Monitoring review quality is
essential to maintain product quality.  Automating the integration
queue potentially denies you this quality opportunity.

------------------------------

Subject: 4.3.  How do I enforce coding standards?

The "develop_end_policy_command" field of the project configuration
file is for this purpose.  If this command fails, the change may not
leave the _b_e_i_n_g _d_e_v_e_l_o_p_e_d state.

For example, if you wanted to check that all files conformed to
project coding standards, you could run the hypothetical
"check_standards.sh" script (a project source file, of course), using
        develop_end_policy_command = "sh ${source check_standards.sh}";
This script would use the _a_e_l_c_f command to obtain the list of files to
be checked.

------------------------------

Subject: 4.4.  How do I get dates printed before and after build
        commands?

The _b_u_i_l_d___c_o_m_m_a_n_d field of the project configuration file can also be
used to do more than just build:
        build_command = "set +e; date; cook ...; x=$?; date; exit $x";
You need to be careful about the -e flag, because Aegis invokes the
shell to run the commands with the -e option, to abort after the first
error.

You may want to upgrade to Aegis 3.0 or later.  In this version, the
times are automatically printed as part of the verbose commencement
and completion messages.

------------------------------

Subject: 4.5.  How do I stop Aegis automatically merging?

The merging behavior is controlled by the "diff_preference" field of
the user configuration file.  See _a_e_u_c_o_n_f(5) for more information.
There are also three command line options to the _a_e_d(1) command which
can override the preferences, see _a_e_d(1) for more information.

To stop the automatic merging, add the line
        diff_preference = no_merge;
to the .aegisrc file in your more directory.  To specifically perform
a merge after that, you will need to use the "aed -merge_only"
command.  There is an "aem" alias for your convenience.

------------------------------

Subject: 4.6.  How do I modify which developer is assigned to a
        change?

There have been times when we have one developer working on a change
and, for one reason or another, we need assign that change to
different developer before the change is at a point where it can be
integrated.  Is there a way to tell Aegis that a new developer has
been assigned to the change so that it would change files permissions
accordingly?  (My thanks to Mark Meuer <markm@endo.com> for this
question.)

Yes, you need to use the _a_e_c_h_o_w_n(1) command.  This command may be run
by a project administrator to reassign a change to a different
developer.  Because _c_h_o_w_n(2) does not work over NFS, a new development
directory owned by the new developer is created, and the change files
are copied, before the old development directory is deleted.

------------------------------

Subject: 4.7.  Do I have to type all the configuration examples in the
        User Guide?

No, you do not.  The lib/config.example directory contains a number of
files with the configuration command from the User Guide ready for
inserting into your project configuration file.

------------------------------

Subject: 4.8.  Is there a way to recreate a previous baseline?

For example, let's say we have shipped one version to a customer and
since then made 30 changes to the baseline.  When the customer calls
in with a failure report that we can't reproduce, how can I easily
rebuild the baseline from 30 changes ago to help track down the error?

Yes, it is possible to recreate a previous baseline.  You need to
follow these steps:

1. Determine which delta was shipped to the customer.  This is easiest
if you embed the version supplied by Aegis into your executables at
build time.

2. Create a change a change (you want to fix the bug, right?)  and
start developing it.

3. Copy all of the project files into the change, using the delta
number determined in step 1.  Use these commands:
        aecd
        aecp . -delta N
where N is the delta number from the first step.  Files created since
the delta will be copied into your change as empty files, leave them
alone for a while.

Note that you need Aegis 2.3 for directory copying to work correctly.
Earlier versions will need to use
        aecd
        aecp `aegis -list project_files -terse` -delta N
Note the backward quotes.  The above can be abbreviated, its just long
so you can see what it is doing.

4. Build the change as normal.  This will completely rebuild the
version sent to the customer.  Note that a number of things are beyond
Aegis' scope, like operating system updates and compiler updates.
These can have an effect in accurately reproducing what was sent to
the customer.

5. Find the bug and fix it, as you would normally do.

5. Merge the change.  This will bring the files up to the most recent
version, and merge the bug fix with the current version.

6. You can now uncopy all of the files which are unchanged.  Aegis
provides a fast way to do this
        aecpu -unchanged
This command behaves like aecpu, but it goes hunting for files which
are the same between the baseline and the development directory.  Note
that you must do this step after the merge.

------------------------------

Subject: 4.9.  How do I stop it using the pager?

Aegis automatically redirects the output of listing and help into the
pager program described in the $PAGER environment variable, or _m_o_r_e if
not set.  This is only done if aegis is running in the foreground and
the output is a terminal.

The simplest way to stop the use of the pager is to pipe the output
through cat.  A more elegant method is to use the -No_Pager option.

If you want to permanently disable the pager, set the following line
in your .aegisrc file:
        pager_preference = never;
If you want to use the pager now, you will need to use the -PAGer
option.

------------------------------

Subject: 4.10.  Why does develop end complain about builds?

Why does aede complain that "this change must successfully complete an
'aegis -Build' before it can end development" but I have just done a
successful build?

There are two possibilities: time stamps and architectures.

------------------------------

Subject: 4.10.1.  Build Time Stamps

Aegis tracks time stamps on files and builds, etc, to determine when
files are out of date.  If time clocks on various networked machines
disagree, it is possible for Aegis to conclude that a file or files
are logically out of date.

This problem is mentioned in the User Guide.  Essentially, you need to
install NTP or XNTP.  If you can't do that, run _r_d_a_t_e(1) on your
client machines from cron, to sync their clocks with the file server's
clock.

------------------------------

Subject: 4.10.2.  Build Architectures

The "aede" can also complain about builds when you have changed the
architecture field of the project configuration file, but have not yet
updated the change's attributes to match.  This can also happen when a
separate change updates the architecture field, and all existing
changes suddenly get this mystery error.

It happens because the default architecture is "unspecified" in the
change attributes (use "aeca -l" to take a look).  When the project
configuration file changes, the required architecture, according to
the change's attributes, is still "unspecified".  To fix, use "aeca
-e" and edit the change's attributes to match the architecture names
in the project configuration file.

You may wish to upgrade to version 3.0, which checks for this, and
prints a suitable error message, with a suggestion to edit either the
project configuration file or the change attributes.

------------------------------

Subject: 5.  Internationalization

This section discusses a number of issues surrounding
internationalization, and the effect it has has upon Aegis and its
error messages.

------------------------------

Subject: 5.1.  Say What?

Internationalization is the process of modifying code so that it may
produce messages in the native language of the user.  A data file is
supplied for each supported language, containing the strings to be
substituted for error messages and other text produces by a program.

------------------------------

Subject: 5.2.  So why are the error messages So Bad, now?

There is a set of default error messages in the code itself.  These
error messages are used if the localization file cannot be found, or
if the message is absent from the localization file for some reason.
These messages tend to be in the "programmer cryptic" language, and
the English localization has probably not been installed correctly.
The English localization *needs* to be installed.

There is also a small, slight, tiny (cough) possibility that the
necessary code changes have introduced bugs into some error reporting.
(And we need bugs there like we need a third arm pit.)  Please report
any problems immediately to the author.

------------------------------

Subject: 5.3.  What controls which language is used?

There are a range of environment variables, depending on your
operating system.  The most common is the LANG environment variable.
The default is "en" (for English) if nothing is specified.

------------------------------

Subject: 5.4.  What localizations are available?

Only English is available at this writing.

More may become available if there are any generous bilingual Aegis
users out there, who want to provide a localization file in another
language.

------------------------------

Subject: 5.5.  So can I change the text of error messages?

Yes, you can, but it is not advised.  Seriously.  (I'm going to regret
admitting this, so I'm not going to tell you how.)  If you have
suggestions for improving error messages, please email them to the
author.

------------------------------

Subject: 6.  Branches

This section discusses a number of issued surrounding branching.

------------------------------

Subject: 6.1.  What is a Branch?

Aegis treats branches as "big changes".  This allows much of Aegis'
development model be be applied unchanged, but still allow the
development of projects to be broken down into fine grained pieces, or
aggregated into large "release sized" chunks.

------------------------------

Subject: 6.2.  What is an Anabranch?

Aegis' branches can end.  This is a consequence of treating branches
as "big changes".  Logical places to end branches are times like when
a release of the software is made.  The geographic term for a stream
which breaks off and rejoins downstream is an anabranch.

Because branches can end, combined with the fact that branches are
"big changes", this means that you use "aede" to end development of
the branch.  After that, it is just like any other change on its
parent branch.

------------------------------

Subject: 6.3.  Do branches have to end?

No.  You are not required to end development of a branch, just as you
are not required to end development of a change.  In particular, the
project trunk is an unnumbered branch which never ends.  How you
manage your project is up to you.

------------------------------

Subject: 6.4.  Why are branches called projects?

In order for the branches to be "big changes", there are times when
you will refer to the branch as a change to its parent project.  In
order for branches to have changes, there are times when you will
refer to them as a project.

The conversion between the two is intended to be simple.  When you
need to refer to a branch in its project role, join the branch's
parent project name to the branch's number with a dot; _e_._g_. "-p
aegis.1.2".  When you need to refer to a branch in its change role,
separate the branch's project name from the branch's number at the
last dot; _e_._g_. "-p aegis.1 -c 2".

------------------------------

Subject: 6.5.  Why must aed be used when integrating a branch?

Because branches are "big changes" and follow _a_l_l of the things a
change must do, including aed.  The only time a branch is writable is
at integration time for a change on that branch.  Thus, the aed for
the branch is done between aeib and aeipass.  The trunk doesn't
require it, because you never say aede to the trunk.

------------------------------

Subject: 6.6.  How come the branch baseline is incomplete?

The branch baseline is the development directory for the "big change"
represented by the branch.  Just as a developers development directory
only contains the things being worked on, and their implications, so
does the branch baseline.

This means that wherever you specify a search path (-I, VPATH, _e_t_c) to
look first in your development directory and then in the baseline, it
must also look in each of the branch's ancestors' baselines.  Aegis
provides a "$search_path" substitution telling you where to search;
this is usually used in the "build_command" field of the project
_c_o_n_f_i_g file.

The "aefind" command may also be used to perform actions similar to
use usual Unix find(1), but across the Aegis search path.

------------------------------

End of aegis.4.24.3.faq Digest
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