Configuring an iBook Cart, Part 1

2002 – In a few weeks, I have to train my colleagues how to check out, use, maintain, and return one of several iBook carts our school has purchased. In the meantime, the carts have to be prepared with certain multiple user settings, passwords, site licensed software, and network settings.

Obviously, the simplest thing to do would be to prepare a disk image with all the proper settings and copy it to all the iBooks, then customize settings such as the IP address. On the other hand, teachers are asking why can’t we use the carts now – and I haven’t tried to make a master CD yet.

Better Safe than Sorry

Rushing into deployment is one of the things that got Henrico County schools into so much trouble and continues to cause echoes in places like Maine’s scheduled deployment. We’ve taken the slow approach, studying the iBooks in situ in a few classrooms, working out the bugs of deployment for the non-technically minded. Nevertheless, I may have to sit down and configure the machines one at a time (or rather, my TAs will).

In this series of articles, I will share what we’ve learned as we do this work.

I’ve already written a review of the cart as purchased. Each cart contains 16 iBooks (the 500 MHz model), an ethernet-capable Epson printer, a 5-port ethernet hub, and an AirPort Base Station (Summer 2001 version).

One thing I don’t think I mentioned was that the carts were already worked over by our district technicians, who installed Microsoft Office (sans expansion packs) and some other site licensed software like Timbuktu. Since our LAN wasn’t finished at the time (and still isn’t, as a matter of fact), they couldn’t complete the configuration, so we’re going to tackle it ourselves to speed up deployment. They didn’t deal with the multiple users configuration, either.

Multiple Users

When setting up Multiple Users, you can specify a login with certain privileges set. For our laptops, we set up the following login IDs:

  • technology: This is equivalent to the root user, the owner of the machine. In fact, we just took the owner identity and renamed it. This user can change any setting on any control panel and see all the other users’ files.
  • teacher: This user has almost complete access but is not authorized to change the IP settings or reconfigure the permissions on multiple users.
  • student: Student users can use selected applications, save files on the desktop, and connect to servers via aliases. Most control panels, including AppleTalk, TCP/IP, Appearance, and so on are disabled. Most compiled scripts are disabled. The script editing application is disabled. iTunes is disabled. Access to changing the proxy settings of the Web browsers is off. Even though our laptops won’t surf without the proxy in place, and we don’t sent these machines home, we decided not to take chances.

The library also has a user called Internet that can browse, while the default student user cannot, since our students must have an Internet permission card to use the Internet.

AppleTalk or IP?

Another wrinkle I discovered since my initial review is that the Epson printer, while addressable as an LPR printer to Windows computers, is addressable to Macs only as an AppleTalk-over-Ethernet printer; the LPR printer function in the Desktop Printer Utility, required for IP-based printing, is not available. For most of our classrooms, that’s not a big problem.

Unfortunately, in my classroom all AppleTalk packets are blocked at the school router level, so I have to unplug the ethernet cable and disable all Web surfing for students to print to the cart printer. Whatever solution we come up with has to work around this problem, which occurs in approximately 5% of our classrooms. Including, ironically, Mr. Mac Head’s room (that would be me).

At this point you should go ahead and copy this text into the email you’re about to send me: “Why don’t you reconfigure the router to pass the AppleTalk packets? It should be a simple matter to fix if you know how to configure your router.”

No AppleTalk for You!

The answer to your unsent email is that it is the stated goal of our IT department to eliminate all AppleTalk devices from our network. They say it’s an errant AppleTalk device (such as a printer that so far we have failed to locate) that is causing the problem in the first place by “flooding” the network zone (subset of a larger LAN) with packet traffic.

We have eliminated AppleTalk-to-ethernet adapters, Personal LaserWriters, and all computers running Mac OS versions lower than 8.1 from the network, and we still haven’t found it.

AppleTalk, in its original form way back in System 6 and earlier, identified devices on the network and their status by continually sending out announcements about it. This is how your printer pops up in the Chooser after a few seconds.

Later versions of the Mac OS, however, just do the query/response dance when a new device is plugged in or when data is about to be sent. Otherwise it sits and behaves itself, or so I’m told. This “chatty AppleTalk” business is one of the common complaints IT managers use against Apple products, and I’ve written about it before. Apple simply doesn’t do a good job defending itself against this kind of criticism.

Publisher’s note: The original AppleTalk specification allowed up to 255 devices on a network and constantly sent inquiries to the network looking for new devices or disconnected devices. That was especially problematic when there were AppleTalk devices on both ends of a WAN (Wide Area Network), like connecting to another Mac over the Internet. Part of the problem was the amount of data each Mac and device sent over a 230.4 Kbps network, quickly eating into total bandwidth once you had more than a few dozen Macs and printers on LocalTalk.

Moving to a 10Base-T ethernet network did a lot to alleviate this, as it has 40x the bandwidth of AppleTalk. A protocol that eats up perhaps 20% of the bandwidth over PhoneNet cabling as data packets move from device to device on a very congested network would see that drop to 0.5% on 10Base-T ethernet – and using a switch rather than a hub further reduces network traffic, since all connections are device-to-device, never being seen by anything else on the network.

AppleTalk Phase II addressed the “chattiness” of the original specification way back in 1989, somewhere around Mac System 6.0.4. If anything, AppleTalk Phase II is less chatty than the TCP/IP protocol used on modern networks and the Internet, let alone all those NETBIOS packets Windows PCs constantly put on the network.

Consequently, I’ve had to learn more about printing over IP and file sharing over IP than I ever wanted to know. It’s also interesting that my classroom and department file servers had to be switched to IP addressing – but the built-in file sharing functions in Mac OS 9 still would not work until I installed AppleShare IP and turned on IP file sharing from there. I also had to consolidate two well-organized servers into one disorganized and labyrinthine system to make it run on the one machine for which I have an AppleShare IP license.

Besides, I don’t know where the router for my classroom is. The circuit breaker panel in my room does not control my room’s power, for example, which sort of outlines the problem for you. There are routers downstairs in a storeroom in the office, but the labeling on the router cables, where it exists, doesn’t match the labeling of the ports in my room. We’re not allowed on campus on weekends to experiment with such things, either.

More to the point, the only routers I’ve ever configured have been side effects of configuring AirPort Base Stations, so you’d have to put a manual in my hands before I could accomplish much. So I have to work with the tools Steve bestowed upon me to solve my problems.

My advice to the folks in a normal environment: Use AppleTalk if you can, because it’s easier. If you can’t, IP is just a little more difficult, so go ahead and take the plunge. If you’re behind a firewall, you don’t have to worry overmuch about connections from the outside world, at least.

Part 2

Next time I return to this topic, I’ll tell about how we Figured and Configured the Base Station. Also in the future is setting up a file server so students can transfer work to your permanent computer (since iBooks don’t have floppy drives). And finally, there are a bunch of little things you might need to know, such as how to control the trackpad – a surprising number of teachers have never owned a laptop, never used a trackpad, and don’t know how to to tell their students how to control the cursor.

Stay tuned.

Keywords: #appletalk #chattyappletalk #appletalkpackets #ibookcart

Short link: http://goo.gl/IA44pc

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