APDL Eductation Resources/APDL Eductation Resources.iso/programs/network/simnet/!SimNet/Manual/Chap3

Text File | 1994-10-22 | 20.5 KB | 429 lines

Chapter 3 - User Guide

3.1 OVERVIEW

A Network Manager should provide facilities to aid the tasks of the
System Administrator in a number of areas − not just password file
management. In this chapter the functions of !SimNet are
organised into three major sub-sections:

    •    The password file;
    •    The file server; and
    •    The network.

The aim is to provide a single program which allows common
network maintenance operations to be performed from one
location.

Note that interactive help is available in all !SimNet windows. This
help can be viewed by running the Acorn !Help application
available inside the "Apps" folder on the icon bar.

!SimNet interacts with the user in much the same way as any
WIMP application. It is started by double-clicking on its icon in a
directory viewer. It presents information in a number of windows
and is controlled via menus and dialogue boxes. Clicking SELECT
on the icon bar icon displays the Control Panel. This displays
information about the currently selected file server (!SimNet will
manage as many file servers as you have connected to your
network) and has a number of control buttons for displaying the
password file. Password data is displayed in a tabular manner and
may be edited using spreadsheet-like operations. Modified
password files are saved using normal RISCOS Save Dialogue
Boxes.

!SimNet has been provided with a number of features to better
support the initial generation of password files. The administrator
may use any tool and method to create lists of users who require
accounts. Unlike !Manager, all the prospective fields in the
password file can be imported. Thus a spreadsheet package such
as !Schema or !Pipedream can be used to create tables
containing the password data, or even more simply !Edit. As long
as the package can export data in CSV (Comma Separated
Value) or TAB format this is sufficient − the file is dragged and
dropped onto the !SimNet Control Panel to import the data and
convert it to password file format. This feature is particularly
important for the initial creation of a password file where hundreds
of users may be involved. Of course, !SimNet itself can be used
for creating new password files or adding to existing ones, but its
features for tabular editing are more restrictive than a full blown
spreadsheet package.

3.2 THE PASSWORD FILE

Password data consists of one record per user, each record
containing seven separate fields. The fields are defined in the
table below:

Table 1. Password file fields

!SimNet allows such password files to be edited in two modes of
operation:

•    If !SimNet runs on the same station as !Server, then the
password file will be accessed directly for speed reasons.

•    If !SimNet is run on a client station then it will use the File
Manager protocol defined by Acorn. Note that this protocol
has been designed to fit in with the Level 4 !Manager concept
of single user display/update. Loading the password file over
the network into !SimNet can take some time as a result. For
large password files (>100 users) it is recommended that
!SimNet is run on the same station as !Server.

3.2.1 Password File Operations
Several common operations will now be described to illustrate
how the facilities supplied with !SimNet are used. One of the most
common operations will be the initial loading of password file data
prior to an edit session. Password files may be loaded in a
number of ways, here we consider the simplest. !SimNet has been
started on the fileserver itself and so there is a local password file.
To load this file, first click SELECT on the !SimNet icon to display
the Control Panel as shown below:


Figure 1 The Control Panel

The password file section contains a variety of buttons to control
the loading and display of the password file from the target server.
Normally, the administrator wants to see the whole file. To do this
move the pointer to the “display” button and click SELECT. While
the file is being loaded, dialogue boxes will appear to indicate the
extent by which the load operation is complete. For large files
which can take some time to load (1000 users will take
approximately 5 minutes) this gives a positive indication that the
load operation is proceeding. After loading, a window will appear
containing a spreadsheet-like display of the password file entries.

Two example editing operations will serve to introduce the
features provided for updating password files. The two operations
will be (1) change a users space allocation; and (2) change the
Boot Option for each user to "Run".
For operation (1), assume the password file data appears as
shown in Figure 2 below:

Figure 2. Sample Password File Display

The overlaid lower rectangle indicates the cell containing a space
allocation of 488K. To change this to 256K, click SELECT in the
cell, type ^U to clear the cell and type '256K'. Click MENU over the
password file display window, which will activate the main menu.
Choose the File option and then the Save option using the MENU
button. Alternatively press the F3 key with the password window
having input focus. The file save dialogue box will appear. Click
SELECT on the save button to save the updated password file.

For operation (2), use the same steps described above to change
the entry in the upper box from 'none' to 'run'. Then move the
mouse pointer to the column title, where it will change to a down
arrow shape. Click SELECT and the whole column will be
selected, indicated by the cell colours reversing. Then click MENU
and in the Selection sub-menu choose 'Replicate Down'. All the
cells will be changed to 'run'. Save the password file as in the
previous example.

3.2.1 Filtering Password File Names

Refer once more to Figure 1 showing the Control Panel. Within
the Password File section is an input field titled 'Name Filter'. This
is provided to allow large password files to be selectively filtered
for display, thus making editing operations on groups of users
somewhat easier. If for example, there are 1000 entries in a
password file, but editing operations are only required on the
users whose login id begins with 'F', then only the entries
beginning with that letter are displayed if 'F*' is entered into the
input field before selecting the 'display' button.

The 'Name Filter' accepts two wildcard characters to match login
ids against. The '?' character matches any single character in a
name, while the asterisk '*' matches 0 or more characters. The
following examples indicate how the matching algorithm selects
names using the filter:



Note that name filtering is not case-sensitive, as the examples
portray. The filter mechanism selects which items from the
password file are displayed; all entries are read from and written
to the password file independently of the filter. Thus, if a name
filter is set to display all login ids starting with 'F', and edits are
performed on the displayed entries followed by a save, then all
entries in the file are saved.

3.2.2 Selecting Displayed Columns

In addition to name filtering to control which records in a password
file are displayed, it is also possible to control which fields of each
record are displayed. This provides a further possibility for the
simplification of displayed information. Column display control is
provided through the 'Options..' entry on the icon bar menu. To
view the Options dialogue box, click MENU over the iconbar icon,
then select the 'Options..' entry. The dialogue box shown in Figure
3 will appear on the screen.

In the centre of this box is a section titled 'Displayed Fields'; in the
figure this is shown with all column names ticked. Note that the
first column, the login id, is always displayed. To prevent the
display of a particular column or set of columns, just click the tick
boxes with SELECT. Those columns which are not ticked will not
appear in the spreadsheet display. Click in the Save or OK boxes
to save the new settings. If you click on Save, then the newly set
values will be saved for use the next time that !SimNet is started.


Figure 3. The 'Options' window for setting defaults

The Options dialogue box will disappear. Now redisplay the
password data with the new column selections by clicking the
'Display' button on the Control Panel.

If you work regularly with large password files it is worthwhile
adopting consistent usage of these two display control features.
They allow pre-selection of exactly those items which need
editing, and provide for faster interaction with the spreadsheet
display because redraw times are reduced.
3.2.3 Selecting Users

Editing operations, reports and network operations related to
users can all be restricted to subsets of the user population. This
is achieved by allowing rows, columns and individual cells of the
spreadsheet display to be selected. Selection is via the normal
mouse operation of point-and-click, and a selected row, column or
cell is shown in the display with reverse colours.

To select and individual cell, place the mouse cursor in the cell
and double-click with SELECT. An individual cell is not useful to
select on its own, because most operations require a group of
cells to be selected. To select a column of cells, keep SELECT
held down and drag the mouse down or up. Alternatively, to select
a large number of cells in a column, double click in the first cell
move to the last cell, hold down the SHIFT key on the keyboard
and click with SELECT. All cells between the last and first cell will
become selected. Such a selection is useful, for example, when
performing a replicate operation from the 'Selection' sub-menu.

There are fast ways to select whole columns or rows. For
columns, move the mouse pointer to the very top of the
spreadsheet display. As the mouse pointer moves over each
column title it changes to a down-arrow shape. When over the
column required, click SELECT and the whole column is selected.
Similarly when the mouse pointer is moved to the left of each row
it changes from a caret shape to the normal pointer shape.
Clicking SELECT will select the whole row closest to the pointer.

3.2.4 Creating Password Files

Editing existing files is probably the most common maintenance
operation required on a password file. Equally important is the
ability to create new password file entries, or indeed to create
entire new password files ­ this may happen at the beginning of a
school year, for example.

!SimNet provides for this requirement in the most flexible way
possible. New users can be created directly within the
spreadsheet display, or lists of new users can be created using an
editor or database and then imported into !SimNet. The latter
method is normally most useful on initial installation of a set of
users, because a list of names usually exists in one form or
another (e.g. class register).

Assuming a list of names exists in the format required for use as a
network login id, then creating a password file is simplicity itself.
Merely drag the list of names to the !SimNet icon, or to the Control
Panel, and the password file will be created! All other fields will
assume default values, which can of course be edited afterwards.
Alternatively, the import file itself can contain definitions for other
fields, each separated by commas (CSV file) of by TAB characters
in the order defined in Table 1. The extract below illustrates a
suitable file format which will load the six user profiles into the
password file:

FASALANDRE,,F.F1.FASALANDRE,Norm,1024000,None,Y
FASAMANDAM,,F.F1.FASAMANDAM,Norm,1024000,None,Y
FASAMANDMA,,F.F1.FASMANDMA,Norm,1024000,None,Y
FASCHRISWH,,F.F1.FASCHRISWH,Norm,1024000,None,Y
FASDANIECU,RPOSWEEPER,F.F1.FASDANIECU,Norm,1024000,None,Y
FASDANIEHA,,F.F1.FASDANIEHA,Norm,1024000,None,Y

Dragging a file with these contents to the !SimNet icon will
produce the following display:
Note that in this display, the home directory column has been
disabled using the method described in Section 3.2.2.

It is also possible to append new users to an existing file. This is
useful if user lists are in multiple files or are to be incorporated into
an existing password file. Appending occurs if the keyboard
SHIFT key is held down whilst dragging the file of names to
!SimNet. You can also drag the file onto an existing spreadsheet
display, but the SHIFT key must be held down to append the
names.

Batches of new user ids can be created within !SimNet itself. This
facility is available from the main menu under the Edit sub-menu,
or from the Control Panel by selecting the "New Users" button.
Either of these methods displays a dialogue box requesting entry
of the number of new users. Just type in the number required and
hit the RETURN key. New users are added with default names of
the form Usernn, where the numerical part corresponds to that
users position in the password file. Thus, if a password file already
contained 10 users, and 5 new users are added, then their names
will be User11 to User15. All other fields assume the default
values defined by the "Options.." window.

3.3 File Servers

The previous examples have assumed that the password file is
local - i.e. stored on the same machine on which !SimNet is
running. Password files can be loaded, edited and saved back to
remote servers as well. Determination of the source of a password
file for editing is performed using the "Fileserver Status" group in
the Control Panel:

Figure 4. Fileserver Status Group

When logged in to a remote file server, information identifying that
server will be displayed in the fields shown. Next to the 'Name'
field you will notice a small menu icon. When MENU or SELECT is
clicked over this icon, !SimNet will display a menu of available file
servers. Select the server required using the mouse, which will
make that server the current server from which all password data
will be read and will be saved back to. The other fields in the
Filerserver Status Group will also be filled out, to provide a
continuous reminder of which server is being modified.

Use the methods described earlier for loading, editing and saving
local password files - they will work identically for password files
on remote servers. One difference to be aware of is speed of
loading and saving. For very large password files, the load/save
time is slower over a network. To give an idea of the timings
involved, the following table illustrates load and save times for a
local server and a remote server. The network used is ethernet
with the Level 4 AUN software:


Table 3.  Timings for Load/Save (Release 1.1)

The large save time over the network is due to the ineffiences of
the file server protocol at saving the data, particularly for large
user numbers.


Other manager programs deal with just the password file, but
there are a number of other useful management functions. The
password file contains details about where a users files are and
what the users login profile is. There is no information on the
amount of disk space actually being used, or the last time a user
actually changed any of his files. !SimNet provides such facilities
via the 'Server' sub-menu. The menu and its contents appear as
shown below in Figure 5.

The first option is 'Create Dirs'. This a convenient way to create
users home directories if they do not already exist. Select all the
users to have directories created for them, and then follow this
menu option. A 'file save' dialogue box will be displayed containing
a directory icon; drag this icon to the directory in which the user
directories are to be created.


Figure 5. File Server Operations Menu

The next two options are 'Disk Space Used' and 'Date Last Used'.
These provide details on the actual state of a users files. Again,
select a group of users in the spreadsheet display and choose the
appropriate option. A window will appear giving the details of disk
usage for the first user in the list; the window has buttons labelled
'Next' and 'Prev' to allow stepping backwards and forwards
through the list. Use the first option to track down all users
hogging disk space, and the second to find unused accounts or
accounts which should be in use but which are not!

The first three options on the menu operate only locally, i.e. where
!SimNet is running on the same machine as the server program.

The next 4 options (and the last) operate for any server. 'Logged
in Users' will display a window showing the total number of users
currently using that server. 'Logout a user' allows the manager to
explicitly force a user off the system by entering the name
required in a dialogue box. 'Send message' has an obvious use.
The option 'Shutdown server' should be used carefully - it will
close down the target server no matter how many users may
currently be logged in! In day-to-day use the manager may use
the 'Send message' option to warn users of an impending
shutdown and then choose the option to shut down the server.

Note that in Figure 5 the two options 'Logged in Users' and
'Logout a User' are greyed-out showing that they cannot be
selected. This is because these options are only enabled when
properly logged on to the server in question with system privilege.
The last option in the menu, 'Login' can be used to do this. It will
pop-up a dialogue box for entering user id and password, and will
use this information to login to the currently selected file server.

3.4 Reporting

All the operations so far described have been interactive in that
functions are started through menus or dialogue boxes and results
are returned or displayed in windows. !SimNet also provides the
functionality to generate text summary reports on a number of
aspects of a server. These reports are produced in standard Text
files and so may be dragged to directories for saving, into editors
or DTP programs for modification and production or directly to
printers for immediate printing.

The diagram of Figure 6 shows the menu options available on the
'Reports' sub-menu.

Figure 6. Reporting Menu

When any of the items is selected, a file save dialogue box
appears. This is dragged to a directory or onto an application and
the mouse buttons released. This causes !SimNet to generate the
requested report and to save it in the location or to the application
indicated.

The five central options in the menu provide the system
administrator with the means to obtain useful statistical
information on the usage of the server and on the status of user
accounts. For example, the 'Space Used' option will provide a full
list of disk space actually in use for each user. This can be used to
identify anomolous use of the system, by showing users who are
taking unexpectedly large amounts od disk space. The 'System
Accounts' and 'Null Passwords' options are useful to check the
security of the server. In the first all users with system privilege
are listed, while in the second, all users without a password a
listed. Where there is an extremely large number of users in a
password file (>1000) these options provide a quick way of
identifying possible security loopholes. Users showing up with
system privilege who should not enjoy such power can be quickly
tracked down. By checking both reports, users with system
privilege and without a password can also be highlighted, a
situation which should definitely not be allowed to arise!

3.5 Network Functions

Commercial network manager software on other hardware
platforms tend to provide functionality aimed at the maintenance
and status in real-time of network components rather than the
Level 4 concentration on just the password file. The manager
software runs continuously and provides instant feedback on
network components which have failed or are producing abnormal
status information.

!SimNet attempts to provide a small amount of this functionality
where it offers useful behaviour in Acorn networks. Two main
operations are available to the network administrator - one to
produce a connectivity 'map' of the network and the other to test
the presence and operation of any machine connected to the
network.

The 'Network' sub-menu provides two options. These are 'Show
Map' and 'Network Ping'. The first option when selected causes
the program to automatically build a connection map showing the
station numbers and type of each machine connected to the
server. The second requests manual input of a station and net
number in a dialogue box. !SimNet sends a request packet to the
station which would generate a response if the station was
present. Absence or presence of the station is shown by a
displayed message in the dialogue box. This is a quick way for the
administrator to test the connectivity between server and station.