Trawl is an intuitive network management utility that allows its user to gather information from an AppleTalk Internet. It facilitates the manipulation and presentation of the gathered data by various means including exporting to other programs.
• Introduction
Since its inception in 1984, the Macintosh has included both the hardware and software for low cost networking. The foresight shown by the Macintosh design team ensured that developers would write software to take advantage of its inherent abilities. Today the Macintosh is possibly the most widely networked computer and out of these simple beginnings, Macintosh networking has matured to provide faster transport mechanisms as well as advanced services such as file serving, electronic mail, program linking, distributed computing, shared printers, network modems and remote access. The growth and increasing complexity of AppleTalk internets has meant that management of these networks has become correspondingly more difficult. A new type of commercial network software has been developed to facilitate easier management. Trawl seeks to eventually provide many of the capabilities and services of these commercial products in an affordable and simple to use shareware package.
Trawl allows a network manager to selectively scan an AppleTalk internet and produce a pictorial view of the network with the devices and services found represented as icons. From this display, which is similar to the Finder’s display of files, further information may be obtained about specific devices by selecting the desired icons and choosing an action through the available menus. Furthermore, the data obtained through the network scan may be exported to other programs for further use either as a pictorial view of the network or as textual data.
• Program Development
After completing an insipid first year Pascal and Software Engineering course at University, I wanted to apply the knowledge gained to something more practical than the rather useless tasks we were given. This, together with a desire to learn how to use the Macintosh toolbox and an interest in computer networking has lead to my first Macintosh programming effort. Despite the vast range of shareware currently available Trawl is as far as I know a unique network utility.
Early in my design I made a decision not to support System software prior to System 7—I expected the majority of potential users to be network managers of some capacity, and by virtue most (if not all) should be using current software. Trawl is therefore fully System 7 compatible, 32 bit clean, and compatible with virtual memory and 040 caching. I have performed fairly extensive testing on a variety of Macintosh models and found it to be stable on the Mac Plus, Mac LC, Mac LCII, Mac IIcx, Mac SE/30, and Quadra 700.
Trawl was totally built in Symantecs’ excellent Think Pascal development environment. However, I plan to port my code over to C, pending the availability of the next version of Symantecs’ Compiler.
• About The Author
I am a second year Electrical Engineering undergraduate at the University of Technology, Sydney. I have particular interests in computer internetworking and Macintosh software development.
I welcome any questions, suggestions or comments you may have about Trawl or, in the unlikely event, about any bugs you may encounter ;–).
All mail should be directed to:
E-mail: mjlowe@acacia.ccsd.uts.edu.au
Fax: +61 2 8070470
Postal: Michael Lowe
53 Dolly Avenue
Springfield NSW 2250
AUSTRALIA
• Registering Your Copy
Trawl is distributed as shareware. It is not a free product! You may use the program on a trial basis for up to 7 days, but if after this period you decide to continue using it you are obligated to pay the current registration fee of US$10 (or equivalent) preferably in cash. Upon registration, I can send you (electronically only) a registered version. I will also send to you future versions as they are released.
I encourage you to give the Trawl package to your friends, however be sure to give them the whole package and remind them that the copy they receive should be registered!
• How To Use Trawl
This document assumes that you know how to operate the Macintosh and are familiar with basic Macintosh terminology. Otherwise, you should first refer to your Macintosh User’s Guide.
- Initiating a network search
After launching Trawl from the Finder, you will be prompted by a dialog giving you a list of the zones available to search on your AppleTalk internet. Initially every zone is selected and will therefore be searched, however you may deselect the zones you don’t need to search (thereby decreasing the time taken to perform the network search) by clicking on individual zones to select/deselect them. You may also, as a shortcut, click on the “None” button to deselect all zones and then reselect the zones you which to search. When you have completed your selections, click the “Scan” button or hit return. The time taken for the search to complete will vary wildly, depending upon the number of zones you are searching, the amount of memory available to Trawl, and the setting of Trawl’s preferences, however you can generally expect that it will take less than 1 second per zone. The network search executes as a background process, so it is possible to switch to, and work with, other applications while you are waiting.
- The network window
When the network search has completed Trawl will display the results in an untitled window. This window may either be displayed as an ‘Icon’ or ‘Zone’ view. In this ‘Icon View’ the network topology is represented graphically as a ‘backbone’ of AppleTalk zones. Zone names are displayed in alphabetical order across the top of the window and the nodes belonging to each zone are chained underneath. In the ‘zone’ view, zones and the nodes belonging to each zone are presented in a list going down the window. In either view, individual nodes can now be selected/deselected with the mouse using methods that are similar to manipulating icons in the Finder.
- Info Dialog
To obtain more detailed information about individual nodes, you must either first select the appropriate nodes and then choose “Get Info” from the “Node” menu (or press Command-I), or alternatively, double click on the required nodes. You will be presented a window similar to the one below for each node you have selected. This ‘Info’ window provides you with the node information already available from the network window as well as its address, registered sockets and program ports.
- Exporting
You may export the information obtained through a network search as either the pictorial view of the network (as displayed in the network window’s “Icon” view), or as a tab-separated list of every node and their sockets. First you must bring a network window to the front and then choose “Export…” from the “File” menu. You will be presented with a standard file dialog in which you must specify the position, name, and type of the new file, and then click the “Export” button.
- Preferences Dialog
Trawl allows you to control some of its internal settings through a preferences dialog. To access it, choose “Preferences” from the “Edit” menu.
The “NBP Lookup” panel controls aspects of the network search (or Name Binding Protocol Lookup as it is technically known). The “retries” field controls how many times Trawl will search each zone, while the “Timeout” field controls how long Trawl will wait for nodes to reply during each zone search. The default setting for both fields are general settings which will work well for most networks, however the optimum settings are specific to the internet in which you will be using Trawl. They depend upon the number of routers/gateways you have, the physical size of the network and the amount of network traffic present. Unless you understand how each parameter is affected by the characteristics of your network, you probably shouldn’t change the default settings.
The “When Lookup Finishes” panel allows you to control what level of notification Trawl will provide if it is not the foreground application when the network search completes. You have the choice of no notification, a diamond next to Trawl’s name in the Application menu, or a diamond as well as Trawls icon being flashed in the menubar.
The “File Creators” panel allows you to specify what creator Trawl will assign to files it creates when exporting a network window.
- Technical Notes
Trawl performs the network search using the services of the AppleTalk Name Binding Protocol. It will initiate concurrent NBP lookups of as many zones as possible in order to reduce the time taken to complete the search. However, two factors govern how many lookups can be performed in parallel and therefore how quickly the search will be completed.
- The number of concurrent NBP lookups your AppleTalk version allows.
- The amount of free memory available to Trawl to allocate a buffer for each lookup.
You may find how many concurrent lookups your computer allows by checking Trawl’s “About box“ (on most computers I have seen, AppleTalk has a limit of 10), however it is obviously beyond your control, apart from installing a later version of AppleTalk from Apple’s Network Software installer.
The second factor can be changed by adjusting Trawl’s memory setting in the Finder. Trawl must be able to maintain a 10 kilobyte buffer for each lookup during the network search—therefore for a search to complete in the minimum of time, it would typically need to maintain 100 kilobytes of buffers. If Trawl’s free memory becomes critically low during a search, it will stop some lookups and recover the memory used by their buffers—you should therefore allow Trawl enough memory for both the lookup buffers as well as any data that will be created as a result of the search.
During the network search, Trawl attempts to assign an icon to each node’s sockets—to do this it uses a resource ‘sMap’. For every socket, it will descend through the ‘sMap’ list until it finds a match with the socket’s Type—it will then use the corresponding icon ID specified by the resource. The node’s primary socket (the socket that is drawn in the ‘Icon’ view) will be the socket that has a match highest in the ‘sMap’ list. By using ResEdit, you may add your own icons to Trawl (however, they should be marked as purgeable) as well as fields to the ‘sMap’ resource. You may also wish to send me your icons and I will include them in future releases.
• Future Development
I have long term goals and strategies for the development of Trawl, however, at present two factors are hampering my development efforts:
- an acute lack of time, and
- a lack of information resources on Macintosh programming—I don’t have ready access to the old Inside Macintosh series, and most of the new Inside Macintosh books are so far unavailable.
Features that are likely to be added to future versions include:
- Remote control of Macintoshs (by the sending of AppleEvents across a network)
This will facilitate such actions as Shutting Down/Restarting a remote computer.
- Increased number of View options
View by net, node, socket type etc.
- Rescanning a network
This will show how a network has changed since the previous scan.
- Dynamic network views
To show your internet topology in realtime.
- Echo
By sending an AppleTalk ‘echo’ packet to a remote node and timing the delay before it is returned, network performance monitoring is made possible.
- Network monitoring/node failure notification
Trawl will monitor specified nodes and provide notification if they disappear from the network.
- SNMP management station support
Something of a holy grail for network management, however this will require a large amount of work for complete implementation.
No charge may be levied for this program, nor may it be included as part of any package sold for profit without express authorisation from the author. It may be distributed freely via BBSs and other electronic data services that do not explicitly charge for file downloads, that is, do not charge a per file rate as opposed to a per hour rate. Further, no service or distributor may attach additional restrictions to this program or to its distribution. This program must be distributed unmodified, and complete with all documentation and additional programs.
Trawl is provided “as-is” without warranty of any kind, including the implied warranties of merchantability and fitness for a particular purpose. The author does not warrant, guarantee, or make any representations regarding the use, or the results of the use, of the software or accompanying instructions in terms of correctness, accuracy, reliability, or otherwise. The entire risk as to the results and performance of the software is assumed by you. If the software or instructions are defective, you, and not the author, assume the entire cost of all necessary servicing, repair or correction. The author shall not be liable for any damages whatsoever arising out of your use or inability to use this product, even if the author has been advised of the possibility of such damages.
After registering Trawl, you are permitted to use one copy of this software on any single computer, provided the software is in use on only one computer at any time. If you have multiple registrations, then at any time you may have as many copies of the software in use as you have registrations. The software is ‘in use’ on a computer when it is loaded into the temporary memory (ie. RAM) or installed into the permanent memory (eg. hard disk or other storage device) of that computer, except that a copy installed on a network server for the sole purpose of distribution to other computers is not ‘in use’. Also, for each registered copy of Trawl you may make one copy for archival purposes, or transfer the software to a single hard disk provided you keep the original solely for backup or archival purposes.
• Version History
1.0 14 April 1993 Initial release
1.01 6 May 1993 Fixed a build problem that caused certain Macs to crash either with ‘Illegal Instruction’ or ‘Address Error’
Added printing of both the icon and zone views
Windows now remember their positions across ‘quits’
Expanded the list of available PICT and Text creator types
