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PCShare Admin is comprehensively described in
3 "PCShare Admin". The following paragraphs only describe options which are usually not needed in a standard installation, and/or options which need to be configured by the system administrator.

During the installation of PCShare, the "install" program automatically creates a public volume with the name "HELIOS_APPS". This volume, which is equivalent to the directory "HELIOSDIR/public", is used to store various applications and utilities as well as the HELIOS documentation in PDF format.

In the server and printer log files (see "Technical notes" in the HELIOS Base manual.), characters with an ASCII value 127 are displayed as underscore ("_"). The same is true for characters with an ASCII value < 32. This is because such characters are interpreted as escape characters by some terminal emulations, leading to corruption of the screen display.

The significance of certain key combinations, especially those which include the Esc (escape) key, depends on the timing of the key presses. For example, pressing the Esc key and then the "A" key with a one or two second pause between key press, has a different effect than pressing Esc and then "A" immediately afterwards.

Due to inevitable but short time delays involved when you start PCShare Admin over a network connection, you may experience erratic problems with certain keys such as Esc, Home, End, etc. If you experience such problems, please use instead the "Ctrl" key equivalents listed in the Key shortcuts section in 4.4.1 "Navigating through the HELIOS Installer" in the HELIOS Base manual. For example, use Ctrl-X instead of Esc.

Certain PCShare Admin windows use line graphics to represent scroll boxes etc. If you start "pcadmin" from a UNIX terminal or a Windows PC, these characters are taken - where possible - from the internal character sets of "pcadmin". If the terminal type, specified in the TERM environment variable, cannot be found internally in "pcadmin", a search is made for a character set file "acsmaps" in the directory specified in TERMINFO and in "HELIOSDIR", in that order. In such cases you need to create a suitable "acsmaps" file in one of these locations. Please refer to the description of "terminfo" in your UNIX documentation for details of the correct structure for "acsmaps".

In unfortunate cases you may find that none of these methods work correctly for line graphics on your host, and that the scroll boxes are drawn using other characters. For example, the line graphics symbol for a cross may be replaced with a "+".

Furthermore, some terminal emulations are buggy. If you see invalid characters on the screen, or it looks scrambled, refresh the screen with Ctrl-R.

In a network of several UNIX hosts your system administrator may have installed a network-wide user and group database such as NIS (Network Information System, formerly called Yellow Pages). See 3.4 "Configuring Users".

Your host may be configured with a secure option (sometimes called the "shadow password" method) instead. On IBM hosts you may have IBM "Extended Security" installed. It is rare to have NIS and a secure option on the same network. PCShare Admin supports all of these methods.

All of these systems use sets of files for user and group data different than traditional, standard UNIX installations. Although PCShare Admin is compatible with all these systems, and recognizes their presence automatically, it is outside the scope of this manual to describe the various sets of files which are accessed by PCShare Admin in this case, since this can vary considerably between different hosts and operating system versions.

In a standard UNIX installation, PCShare Admin gets user information from the UNIX system file "/etc/passwd" and "HELIOSDIR/var/conf/passwd" (HELIOS password file), with the exception of the list of groups to which the user belongs, which is taken from "/etc/group". These are the files that are changed when you create or change users.

Group information is taken from the files "/etc/group" and "/etc/passwd". These are the files that are changed when you create or change groups.

When you export a volume or a printer, the configuration is written to "HELIOSDIR/var/conf/Preferences". If you choose character translation or a PostScript printer, the UNIX print command includes the "pcfilter" utility (see pcfilter in 5.3 "Print server utility programs"). "pcfilter" replaces the "dfilter" program provided by earlier PCShare versions, and has a much wider range of features.

The server log file is taken from
"HELIOSDIR/var/adm/server.acct". See details in 3.10.1 "Server Log File" and in the HELIOS Base manual chapter "Server log file structure".

The printer log file is taken from
"HELIOSDIR/var/adm/printer.acct". See details in 3.10.2 "Printer log file" and in the HELIOS Base manual chapter "Printer log file structure".

The program versions and configuration list is taken from the file "HELIOSDIR/var/run/Versions ". Details can be found in 3.10.4 "Program Versions".

In TCP/IP networks it is essential to have a unique IP address for each TCP/IP node on the network. Thus each PCShare client needs a unique address. If the network is connected externally to the Internet, each IP address must be unique worldwide too, and must be allocated by the appropriate regulatory authority. See 2.1 "Introduction to PCShare and TCP/IP" for more details.

Furthermore, in the case of Ethernet, each network card has a hardware address which must be unique for each local network segment. This is taken care of automatically, usually by the network card manufacturer.

Each PC client in the PCShare network needs a unique IP address, and there are three ways - apart from local configuration - that it can get this:

Client IP addresses are allocated by manually editing the appropriate UNIX system files ("/etc/ethers" and "/etc/hosts" or their NIS equivalent). See your UNIX documentation for details.

Client IP addresses are allocated by manually editing the appropriate UNIX system files ("/etc/bootptab" and "/etc/hosts" or their NIS equivalent). See your UNIX documentation for details.

Client IP addresses are allocated by the "pcshare" server and stored in "HELIOSDIR/var/conf/ethers.pcs" on the host. This method, called dynamic address allocation, is less work for the system administrator, especially in large networks. You can configure this option with PCShare Admin.

With c) via PCShare Admin, which is the recommended method, clients initially have no host name, and need to have one allocated manually in "/etc/hosts" (or its NIS equivalent). Otherwise, PCShare log files or programs such as "swho" (see HELIOS Base manual) only show the PC's IP address rather than the PC's given name. You can use the Client Activities for `<client>' window in PCShare Admin to display each client's current IP address in dotted-decimal notation.

It is also possible to use a combination of all three methods on the same network. The PCShare client sends a "boot" request to hosts on the same network segment in order to get an IP address. If a PCShare server receives this boot request, and if it is configured as a bootserver, it first checks the appropriate UNIX system files for the PC's IP address, and then looks for an entry in "HELIOSDIR/var/conf/ethers.pcs". An address is allocated automatically if its Ethernet address is not already listed in either of these two places. The allocated address is then appended as a new entry in the "ethers.pcs" file to make sure that the client gets the same address in the future, too.

Important: Make sure not to use overlapping IP ranges, e.g. when using a combination of all three methods since this would lead to severe IP number allocation malfunctions.

"ethers.pcs" documents the relationship between network hardware address and IP address for dynamically allocated client IP address, together with the date of last change for each entry. It is updated by the "pcshare" server program automatically - whenever a client connects to the server for the first time, it is allocated a new unique IP address if it does not already have one in this file (or by methods a) or b), in "/etc/hosts", "/etc/ethers" and
"/etc/bootptab", respectively).

"ethers.pcs" also contains information on a range of IP addresses which have been set aside by the system administrator for dynamic allocation.

Furthermore, a mechanism is provided to age entries which have not been used for a specified period of time, i.e. to delete them from this file automatically. For example, aging will occur if the PC is no longer used for server access, or if you initially allow the PC's IP address to be allocated dynamically, and then add an entry for the PC to the standard UNIX system files. For more details, see the preference dynage in 6.1.1 "PCShare preferences".

If you delete client entries from "ethers.pcs" manually, dynamically-configured clients will be allocated a new IP address automatically, but it probably will be different to the one before.

Primary: 192.9.201.33-192.9.201.39
Primary: 192.9.201.41-192.9.201.44
#
#ethernet addr. internet addr. last change date
#
2:60:8c:2:ad:6c 192.9.200.60 Sat Feb 19 18:20:51
00:00:6b:81:39:12 192.9.200.11 Fri Nov 12 15:00:33
09:00:07:ff:ff:ff 193.9.201.11 Fri Nov 12 15:00:33
.
.

In this example, two ranges of IP addresses have been set aside by the system administrator for dynamic allocation. If your PCShare server has more than one network interface, the interface(s) to be used for servicing client boot requests is/are determined automatically from the specified range(s).

"HELIOSDIR/bin/pcsaddr" can be used on a primary PCShare bootserver to update the "ethers.pcs" file on the fly. A secondary PCShare bootserver will learn changed information from the primary bootserver as described in Primary and secondary bootservers below.

pcsaddr -a macaddr addr
adds a combination of IP address <addr> and client hardware address (macaddr) so that next time the client with hardware address <macaddr> will receive the IP address <addr> when booting.
Example:
pcsaddr -a 2:60:8c:2:ad:6c 192.9.200.60

pcsaddr -s hostname addr
sets the <hostname> for IP address <addr> so that next time the client which receives IP address <addr> during boot up will also receive a resolvable host name. The IP address must already be available to the PCShare master process, e.g. either listed in "HELIOSDIR/var/conf/ethers.pcs" or added before, by using "pcsaddr -a". <hostname> must only contain digits 0-9, and characters a-z, A-Z.

Note: "pcsaddr" will only do rudimentary consistency checks and addresses or names given must comply with the DHCP specification.

If your network has more than one PCShare server, you can optionally configure an additional "secondary bootserver" as a backup to guarantee network availability if the main PCShare server is down for any reason. Configuration is best done with PCShare Admin.

The syntax of "HELIOSDIR/var/conf/ethers.pcs" is slightly different for secondary bootservers. The following is an example of "ethers.pcs" for a secondary bootserver:

Secondary: 192.9.201.32 helios (name of primary bootserver)
Disabled: 192.9.201.50
#
#ethernet addr. internet addr. last change date
#
2:60:8c:2:ad:6c 192.9.200.60 Sat Feb 19 18:20:51
00:00:6b:81:39:12 192.9.200.11 Fri Nov 12 15:00:33
09:00:07:ff:ff:ff 193.9.201.11 Fri Nov 12 15:00:33

Specifying Secondary as bootserver state allows PCShare to become a backup DHCP server. You then will be asked to enter the IP address of the primary bootserver, which is needed to keep in sync with the current list of PC clients. The secondary bootserver then gets the rest of the required configuration information automatically from the primary bootserver. For this to take place, the secondary and primary bootserver must both be running simultaneously at least once while a dynamically-configured client tries to boot.

The Disabled entry disables the servicing of client boot requests on the specified interface. Do this to disable the servicing of boot requests on the network segment if there is already another bootserver.

Note: If your network has two or more hosts which are also DHCP server and uses NIS, we recommend that you use the Disabled option to disable servicing of boot requests on the interfaces of all other hosts. Else, all hosts will answer boot requests for clients which are configured statically in "/var/yp/hosts" and
"/var/yp/ethers" (or equivalent).

For instructions and examples on how to configure IP addresses and host names with the "pcsaddr" tool see Configuring IP address and host name with "pcsaddr" above.

HELIOS PCShare 3.1 User manual