Networking an Amiga to a PC

by John Crookshank

Thanks to the inclusion of Screamernet with Lightwave 4.0 and higher, you may use a single copy of Lightwave to render your work on multiple computer systems. This greatly speeds up your rendering time, and if you have several computers around, Screamernet is flexible enough to allow you to use Modeler on one system while the others are busy rendering. Screamernet is even flexible enough to allow distributed rendering among computers that are not of the same type. In this case, you must own at least a single copy of Lightwave for each platform that you intend to use. If you have both Amiga(s) and PC(s), you only need a single copy of Lightwave for Intel and another copy of Lightwave for Amiga. Even if you have only one computer, Screamernet has a benefit for you: you can use Screamernet to automatically batch render several scenes without intervention. This is quite handy if you have some smaller scenes and want to render them overnight.

But before you can ‘start Screaming’, you have to have a network up and running. Screamernet will use your existing network, it will not do the networking for you. The first and hardest step is getting your systems networked together. Is it worth the time, effort, and expense? If you have multiple computers and use Lightwave to make a living, the answer is a resounding yes. Although this article is aimed at Lightwave owners with both Amigas and Windows systems, much of it will also apply if you have MACs, SGIs, or other computers around. Since Lightwave for the MAC will soon be available, MAC users can use the same basic steps to join their MACs to PC’s to Amigas to SGI’s to….

There are several things that Screamernet will not do for you. It won’t speed up rendering of single images, such as when you hit F9 in Lightwave. It won’t help with Modeler at all. Screamernet will not render directly to Flyer clip, AVI or other animation files, only single images. Whenever you use multiple computers to render, you can no longer render directly to a video drive like the Flyer, Perception, or PAR. Even with absolutely identical systems, the frames will arrive at the disk recorder out of sequence. To prevent this, you will have to render to a system drive first, and when all the frames are finished, move them into the Flyer, PVR, or PAR afterwards. There are some third-party add-ons for Lightwave being created that promise to deal with this issue, but they are not available yet. If you have a Flyer system, there is a Flyer Arexx program that will handle this for you and take all the output frames from a Screamernet network and record them to a Flyer clip in the proper order, regardless of the number of systems that you have rendering. The name of that program is ‘WaitClip.rexx’. We’ve used WaitClip.rexx with our Flyer ever since NewTek ported Lightwave to Windows and we added a Raptor3 to handle all our rendering.

The basic requirements to network your systems together are:

A Windows system running either Windows 95 or Windows NT.

An Ethernet card for the PC.

NFS Server and/or NFS Client software for the PC.

An Amiga running AmigaOS version 2.1 or higher.

An Amiga Ethernet card.

INET-225 TCP and INET-NFSd software or AmiTCP and Samba software.

Ethernet cables and connectors.

Pad of paper for notes.

Patience…

Some general notes on the hardware and software are in order first. I have seen a few "Help! I bought these Ethernet cards, and they have different connectors. How do I…" messages in the newsgroups, so let’s save you that hassle first off. To begin with, we should discuss the 3 most common types of network hardware. These are 10-Base-T, 10-Base-2, and 100-Base-T.

100-Base-T Ethernet cards are faster and more expensive than 10-Base-T or 10-Base-2 cards, but there are no 100-Base-T Ethernet cards for the Amiga, so we can dismiss this type right away. If you buy a 100-Base-T Ethernet card for your PC, it will not be compatible with any of the Amiga Ethernet cards.

10-Base-T cards use a twisted pair wiring style and require an additional purchase of a 10-Base-T Hub in order to connect the systems together. Although this is the most popular type of network cabling used in the PC world, there are only two Amiga networking cards in existence that support 10-Base-T, and since we are intending to set up a simple network, we can do without the extra expense of buying a 10-Base-T Hub. 10-Base-2 Ethernet uses coax cable, and while it is not quite as popular in the PC marketplace, PC Ethernet cards that support 10-Base-2 are readily available. Many manufacturers have "Combo" cards that have both 10-Base-2 and 10-Base-T connectors on them, and you can just select which connector that you wish to use. If you purchase a PC "Combo" style of Ethernet card with both 10-Base-T and 10-Base-2 connectors, you can then purchase any Amiga Ethernet card and be assured that it will be compatible with it. Using the coax 10-Base-2 cabling is by far the easiest and cheapest network to set up, and there are no performance advantages to using one over the other on a small and simple network.

A word of warning concerning PC Ethernet cards: Do not purchase the cheapest card that you can find. Buy a good card that uses 32-bit drivers, and uses a PCI slot if possible. I have recently been contacted by a user who stated that after adding an Ethernet card to his PC that Lightwave renders half as fast as it did before. Yes, this is actually possible. A recent CRN Labs comparison between a bunch of Ethernet cards did indeed show that some of them used a lot of available CPU horsepower just to maintain the network. There were actually a couple of cards that kept the CPU up to 75% busy when they were installed! Be SURE that you purchase an Ethernet card with 32-bit drivers for Windows 95 or Windows NT, and get a PCI card if you have an available PCI slot, and you will probably be OK. Stay away from the ‘$50’ Ethernet cards, there’s a reason why they are so cheap.

Almost any Amiga Ethernet card will work fine in your Amiga. However, I have heard from NewTek that the ASDG Lan Rover (EB920) cards do not work with AmiTCP, so you should probably avoid that brand. Unfortunately, Amiga Ethernet cards will cost over 3 times as much as a PC Ethernet card, but once you get things set up and running smoothly, you’ll wish you had networked your systems long, long ago.

Getting your Windows systems networked together is very easy. Windows 95 and Windows NT (all platforms) come standard with all the software required in order to share files back and forth between other Windows systems. You only have to purchase the Ethernet cards and cables. If all you have are Windows systems, networking them is a real snap. Unfortunately, the networking software included with Windows will not directly allow file sharing with any other types of computers.

When talking about networking software, you will hear the terms Client and Server. If you have Server software installed on your system, the other computers on the network running Client software can ‘see’ your computer. They can connect to your drives, but you can’t connect to theirs. If you install Client software on your system, you can connect to any system that has Server software running. The Server application makes the resources available, and the Client application does the connecting. Each Client/Server setup is a one-way connection. Fortunately, you can run both Client and Server software at the same time, and so can all the other systems on your network. This is referred to as a peer-to-peer network. All the systems are ‘equal’ as far as access is concerned.

This is a very cool arrangement, since you can get at any graphics file that is on any computer you have, including PAR, PVR, and Flyer drives. Yes, you can have a remote computer directly use Perception or Flyer video clips as image sequences without having to break them up into frames first. And you can send rendered frames from your networked computers to a Perception or Flyer for playback. This feature alone makes the expense and work of setting up a network worthwhile.

Screamernet requires a network where all your systems can connect to a common drive that contains the scene file and all it’s elements, as well as a common drive to save all the rendered frames to. Screamernet does not require a full peer-to-peer network system, but you get the most flexibility in sharing your graphics files between computers and applications if you set up a full peer-to-peer network.

For a full peer-to-peer network where all your systems can connect to each other, you will need the basic networking software, plus network file sharing Client and Server software for each system. Windows 95 and Windows NT (any platform) already include the basic networking software, you will only have to add NFS Server and NFS Client software to a Windows system to be able to share files with any other type of system.

On the Amiga, you will have to purchase the basic networking (TCP/IP) software, plus a Server package. Both available Amiga TCP/IP packages come standard with NFS Client software, so you will only have to add a Server package to complete the two-way connection desired.

Interworks, the maker of the basic INET-225 TCP/IP software for the Amiga also makes an NFS Server package so you can mount your Amiga drives on your PC system. It requires adding an NFS client package on the PC to complete the connection. The Interworks NFSd package is very easy to set up, and is a standard NFS Server package, so it can be used with virtually any system on the market that has an NFS Client package available for it, such as MACs or SGIs. Interworks has a US office for telephone support, which is a real plus if you have problems with your setup.

The other TCP/IP package for the Amiga is AmiTCP, and although AmiTCP does not offer a NFS Server package, there is a shareware add-on for AmiTCP called Samba. Samba is a Server application that can be used instead of a NFS Server package, but Samba only allows connections from Windows systems. If you also have MACs or SGIs, you’ll need INET-225 and it’s more standard NFSd software. Samba is very cryptic to set up and is very slow, but it works OK once you get it set up. Samba also does not require NFS client software on the PC, it works with the standard Microsoft networking software that is included with Windows95 and WindowsNT. AmiTCP is produced in Finland, and has virtually no US support at all, a ‘feature’ that must be considered carefully.

Before you start doing anything, you need to plan a little bit. You will need to make a list of your systems and usernames, etc. and write these down before you begin. You will need a list of the following:

A name for each computer

An IP address for each computer

A login name for the user who will use each computer

The drive names that you need to make available to the other systems

Keep your names short and simple, and do not use spaces or punctuation in the names. When you are done, you’ll have a list something like this:

Computer name: pc1 (also often referred to as host name)

IP Address: 200.0.0.1

Username: john

Password: Lightwave

Workgroup: workgroup

Computer name: amiga1

IP Address: 200.0.0.2

Username: john

Password: Lightwave

Workgroup: workgroup

If you have additional computers, continue adding them to this list. Use the IP numbers that I have here. Don’t make up your own IP numbers, unless you have an existing network and your network administrator tells you to. The only thing that will change from system to system is the Computer name and IP address. The rest of the data will stay the same on all the systems. Notice that I used the same username, password, and workgroup name on each system, and that I used only lowercase when typing the names, but upper and lower case on the password. The AmiTCP software requires passwords to be in mixed case, but the rest of the settings can be however you want. This will make it easy to remember later, since all your systems will use the same username and password. Be sure and write these down, as you will need this information again later.

We’ll start off with installing networking for Windows 95 since it’s so popular. Windows 95 will most likely automatically detect the presence of your new Ethernet card when you turn the system on, and automatically install the driver software for you or prompt you to insert the driver diskette. If not, load up the Control Panel and select ‘Add New Hardware’. Windows 95 will again try to figure out by itself what you have, but if it does not, you can select ‘Network Adapters’ and then select the "Have Disk’ option to have the driver installed from the disk that came with the Ethernet card.

After the driver for the card has been installed, you’ll need your Windows 95 CD to install the networking software. Make sure that you select ‘Client for Microsoft networks, ‘NetBEUI’, and ‘TCP/IP’ to be installed. You can select ‘Add -> Protocol -> Microsoft -> TCP/IP’ and ‘NetBEUI’ to put these items in the list. When you are finished, the list of networking items should show the following:

Client for Microsoft Networks

Your Ethernet Adapter

NetBEUI

TCP/IP

File and Printer sharing for Microsoft Networks

You will also be prompted to enter your computer name, workgroup name and user name once the networking installation process is started. In the Network panel, select the entry that shows ‘TCP/IP -> Ethernet adapter’ and click the ‘Properties’ button to set up the TCP/IP software. Click the ‘IP address’ tab and click ‘Specify an Address’. Enter the number 200.0.0.1 in the IP Address box, and enter 255.255.255.0 in the ‘Subnet Mask’ box.

Click on the ‘File and Print Sharing’ button and make sure that ‘I want to be able to give others access to my files’ is selected. If you also select ‘Windows Logon’ in the ‘Primary Network Logon’ box, you won’t have to enter a password every time you start up your system. Select OK, and the information will be saved, and your system will reboot.

For the NFS Server software on Intel Windows 95 and Windows NT, I use TropicNFS Server. If you have a DEC Alpha system, Intergraph sells several NFS Client and Server packages that you could use instead. Install the NFS Server software on the PC in a directory of your choosing. In the NFS Server directory, you only have to create a file called ‘exports’ to tell the NFS Server software which drives to make available (export) to the Amiga. Use Notepad to type in the lines below and then save the file as ‘exports’ in the NFS Server directory. My ‘exports’ file looks like this:

# Export root directory of disk D: and E: to amiga1

d:/ 200.0.0.2

e:/ 200.0.0.2

The line starting with the # character is a comment, and is not required. In this example I am exporting my drive D:\ and E:\, and the IP address is the IP address of the computer(s) that will be allowed to connect to the drive. Note that I used a forward slash, not the typical back-slash after the drive name. Add extra lines for extra drives that you wish to make available to the Amiga. If you have more than one Amiga, list all the IP addresses one after the other, such as:

d:/ 200.0.0.2 200.0.0.3 200.0.0.4

This would allow these three systems to connect to your drive D:\. Save the ‘exports’ file, and you’re done on the PC side for now.

The networking installation process is quite similar for Windows NT. After you have installed your Ethernet card, Windows NT might automatically detect the presence of the Ethernet card and prompt you to install the software for it. If not, enter the ‘Control Panel’ and select ‘Network’. You will be prompted for the Windows NT CD-ROM and you can just follow the prompts to select the Ethernet card driver and the networking software components that you want installed. Make sure that you have the following items selected in the list when you are finished:

NetBEUI

NetBIOS Interface

Server

TCP/IP Protocol and related components

To configure the TCP/IP software, select ‘TCP/IP Protocol’ in the list and click on ‘Configure’. When the install process takes you to the TCP/IP configuration panel, enter ‘200.0.0.1’ in the ‘IP Address’ box, and enter ‘255.255.255.0’ in the ‘Subnet Mask’ box. Click OK to save and reboot.

The setup of TropicNFS software is identical under Windows NT, so it won’t be repeated here. At the time of this article, only a Windows 95 version of TropicNFS was available, but it installed and ran with no problems whatsoever under Windows NT on an Intel system. They should have a version created specifically for Windows NT available by the time that you read this. Tropic Software has no plans to make a DEC Alpha version available of TropicNFS, though. If you have a DEC Alpha system, Intergraph has several NFS Server and Client packages available, and their setup will be fairly similar.

Installing INET-225 goes very quickly, and when you run the Installer program included with INET-225, you will be asked for a user name, host name (computer name) and IP number, plus a few other questions, like the name of your Ethernet driver. The Ethernet driver must be installed, INET will not install it for you. The driver will be in the SYS:Devs/Networks directory, and have a name like hydra.device or ariadne.device if you are using either a Hydra Ethernet card or Ariadne Ethernet card, respectively. INET-225 supports a variety of TCP/IP connections, including modem and Internet, so be sure you select the Ethernet option, and use the file requester to point to your Ethernet card driver file in SYS:Devs/Networking. INET-225 picks a ‘home’ directory for you, just accept the defaults. Answer the rest of the prompts as they come up. One of the question panels asks if you want to use DNS servers, and it is ‘on’ by default. Turn this off before continuing. When the install is finished, you will have an icon called StartInet in your INET:C directory. Edit the tooltypes of this icon to remove the parentheses around the (NFSD) option. Drag this icon to your SYS:WBStartup drawer so it starts up every time you start your Amiga..

Install the INET NSFd software, and when you are finished, you will need to edit the file INET:rexx/startnfsd.rexx. Scroll down until you find the line that refers to your ‘exports’. It should look like this:

* The exports variable declares the partitions you wish to export.

*/

exports = 'dh1:/ dh2:/ VideoB:/jonesproject/'

Change the drive names to match whatever drives you intend to make available to your PC. Note the colons and slashes after the drive names. A word here on performance: If you export the entire drive as I have in my example, the access to this drive will be slower than if you just export a single directory, since the PC will have to build a directory table of all the files and directories that it finds when it connects to that drive. In the example, I have made my entire Amiga DH1: and DH2: drive available to the PC, but just the ‘jonesproject’ directory on my Flyer’s VideoB: drive is available to the PC. The PC will be able to access (and delete) anything on drives DH1: and DH2:, but can only access (and delete) what is in the VideoB:jonesproject folder. Limiting access is both faster and safer. When you are done with the entries here, save this file.

Reboot your Amiga, and the INET software and NFSd Server software will be started automatically.

The only thing left to do is to test the NFS connection to the PC. On the PC, start up the NFS Server software.

Back on the Amiga, open a shell and type:

nfsmgr mount pc1:/d N

You should see an icon appear on your Workbench in a couple of seconds with the name N. If you get an error message, either the NFS Servers ‘exports’ file on the PC has not been set up properly or your INET:rexx/startnfsd.rexx file is incorrect, and you’ll need to check to see if you have your exported drives listed properly, and that you have the proper IP address entered there for your Amiga. Double-click on the N icon, and it should open up to an empty window. Select the menu item Window/Show/All Files, and you should see all the folders on your PC’s drive D:\. Start up your favorite file utility program like Directory Opus, and list the drive N:. It should appear and behave just as any other Amiga hard drive partition, except that loading or saving files to/from it will be slower than a regular hard disk.

Repeat the nfsmgr command for each PC drive that you set up for exporting. Note that pc1:/d refers to computer pc1 and drive D:, change these to match your system. Be careful to use the colon and slash exactly as shown in the example. The last part, N, is the name that will show up on your Workbench when it gets mounted. This could be anything that you like, and you can rename it from Workbench at any time, just like you can rename any other disk. Stay with ‘N’ for now, it will be used later in the Screamernet examples. If you want to automate the mounting of your PC drives, you can type the mount commands with a text editor and then save that file and attach an icon to it so you can just mount your PC drives whenever you want by clicking the icon. If you want the drives automatically mounted every time that you start your Amiga, drag that icon into your SYS:WBStartup drawer after the StartInet icon.

All of the PC NFS Client software that I looked at worked through Windows itself, so to mount the Amiga drives there, you only had to open up the ‘Network Neighborhood’ and use the ‘Map Network Drive’ option to mount and open your Amiga drives. If you are using Windows NT, use the File Manager and use the ‘Connect Network Drive’ option in the disk menu. You must assign a drive letter to your Amiga drive. Give the Amiga drive that has your Lightwave or Toaster software on it the letter V. If you want these drives to always get mounted every time that you start your system, check the option ‘Reconnect at logon’ before you click OK to mount this drive. You should see the Amiga drive get mounted within a few seconds, and you can browse or explore your Amiga drive just as if it was inside your PC.

At this point you are done, and can finally get to use Screamernet! Skip over the AmiTCP section and go to the Screamernet section.

Installing Samba is fairly cryptic, and involves studious use of the installation instructions and a text editor. But bear with me, it will all be worth it when you are done.

To begin with, there are two versions of Samba for Amiga available, each written by different authors. The newest version of Samba will appear in Aminet archives under the name Samba-1.9.15p8.lha, and I prefer this version to the first version that was available. It is started as a deamon automatically when AmiTCP starts. It is more robust, and survives a system reboot (either the Amiga or PC) without having to restart the other system. Make sure you get the proper version. In the Internet Aminet archives, Samba is located in pub/aminet/comm/net/.

You will also need a file called ixemul-040fpu.lha or ixemul-020fpu.lha, depending on whether you have an 040 or 020/030 CPU in your Amiga. The ixemul files are located in dev/gcc/ on Aminet sites. When this file is unpacked, you have the files ixemul040fpu.library and ixnet040fpu.library. Rename them to ixemul.library and ixnet.library, and then copy them to your LIBS: directory.

Create a Samba directory in your AmiTCP: directory, and unarchive the Samba files there. Load up and print out the ‘Amiga Installation Notes’ file for instructions on how to perform the file editing and joining. Basically, you have to edit two of the files in the Samba directory, and join several other files before it will all work. The first file is Amitcp:Samba/lib/smb.conf. Load it into an editor and add the definitions of the drives that you want exported to your PC. Scroll down until you see the section that looks like this:

[SYS]

comment = System boot volume

valid users = pcguest

path = /SYS/

read only = yes

public = yes

We need to change this to match the drive(s) on your system that you want exported. If you want to export DH1: and a Flyer VideoB: drive to the PC, change the above entry and use cut and paste to create a second drive entry after the first one so it looks like this:

[DH1]

comment = amiga1 DH1: drive

valid users = pcguest

path = /DH1/

read only = no

public = yes

[VideoB]

comment = amiga1 Flyer VideoB: drive

valid users = pcguest

path = /VideoB/jonesproject/

read only = no

public = yes

The line that starts with comment= can contain anything that you want. When you are in File Manager, this comment will show up next to the drive name when you select the ‘Connect Network Drive’ option. Be careful of how you specify drive names here. Note that the standard colon after the drive name in the ‘path’ line is assumed. Do not actually type a colon in the path to your exported drives. In the second example, I also only exported the ‘jonesproject’ directory on my Flyer VideoB drive instead of the entire drive. I also changed the read only = definition to no, so that the PC can write to these drives. Do not change the ‘valid users’ line, leave it set to ‘pcguest’. Save this file when you are finished entering your Amiga drives for exporting.

Next, you have to edit the file Amitcp:Samba/inetd.conf.addon. It will look like this:

# This is for Samba

# You should modify the arguments for nmbd to suit your setup and network.

netbios-ssn stream tcp nowait root AmiTCP:samba/bin/smbd smbd

netbios-ns dgram udp wait root AmiTCP:samba/bin/nmbd nmbd -n k4315 -G Kampsax -C "Amiga 4000/030 på værelse 4315 (rask@kampsax.dtu.dk)"

You only have to change the stuff at the end of the second line here. Be careful not to change anything else. Change k4315 to amiga1, which is your computers (host) name. Change Kampsax to workgroup, which is your workgroup name. Change what is inside of the quotes to a description of your system. When you are finished, it should look like this:

# This is for Samba

# You should modify the arguments for nmbd to suit your setup and network.

netbios-ssn stream tcp nowait root AmiTCP:samba/bin/smbd smbd

netbios-ns dgram udp wait root AmiTCP:samba/bin/nmbd nmbd -n amiga1 -G workgroup -C "Amiga Flyer"

Save this file, and follow the directions in the ‘Amiga Installation Notes’ file that pertain to joining the various files together. You can use cut and paste in the Amiga ‘Ed’ text editor to do this if you have never used the ‘join’ command before.

Next, load up the file Amitcp:db/ch_nfstab. Cursor down to the very bottom of this file, and enter the next two lines:

pc1:/d N:

pc1:/e M:

The first part of each line, pc1:/d, refers to computer pc1 and drive D or drive E. Pay attention to how the colons and slashes are placed. The last part, N and M, refer to the names that your PC drives will show up as on the Amiga Workbench. These names can be anything that you like, but keep them short and do not use spaces in the names. Again, stick with N: and M: now, the Screamernet examples will expect this. When you are finished, save this file.

And last, load up the file S:User-Startup. Cursor down until you see the section where the command AmiTCP:bin/startnet is located, and cursor up a line or two above that command, and hit Enter a couple of times to open a blank line or two, and add the following lines to the file. Make sure that you add them before the AmiTCP:bin/startnet command line.

assign etc: amitcp:db

assign tmp: t:

assign proc: nil: path

Save this file when you are finished, and this completes the AmiTCP/Samba setup. Whew! Isn’t shareware software just loads of fun? Reboot your Amiga, and AmiTCP and Samba should start up automatically when your system boots up.

To test things out, go to the PC and start up the NFS Server software. Go back to the Amiga and open up a shell and type the following:

ch_nfsmount N:

If you get an error message, either your AmiTCP ch_nfstab file has an incorrect definition, or your PC NFS Server software ‘exports’ file has an error. You should see a disk icon with the name N show up on your Workbench within a few seconds of entering this command. Double-click on this icon, select the Workbench menu option Window/Show/All Files, and you should see all the folders on your PC’s drive D. Repeat this command for M:, and that drive will show up, too. If you want these drives to be automatically mounted every time you start up your Amiga, edit your S:User-Startup file, and put the ch_nfsmount commands at the very end of the User-Startup file.

Samba works through Windows itself, so to mount the drives there, you only have to open up the ‘Network Neighborhood’ and use the ‘Map Network Drive’ option to mount and open your Amiga drives. You must assign a drive letter to your Amiga drive. Give the Amiga drive that has your Lightwave or Toaster software on it the letter V. If you are using Windows NT, use the File Manager and use the ‘Connect Network Drive’ option in the disk menu. By the time you read this, Windows NT 4.0 will be available, and the ‘Network Neighborhood’ option will apply there, too. If you want these drives to always get mounted every time that you start your system, check the option ‘Reconnect at logon’ before you click OK to mount this drive. You should see the Amiga drive get mounted within a few seconds, and you can browse or explore your Amiga drive just as if it was inside your PC.

At this point you are done with the networking, and can finally get to use Screamernet!

Screamernet is documented quite well in the Lightwave 5.0 User Guide, pages 185 - 193, so I’ll just explain what is NOT in the manual - but should be. From the message traffic on the Lightwave sections of the Internet, it is obvious that 90% of the trouble people have with Screamernet is understanding drive paths, especially the relative drive paths as they are used in Lightwave 4.0 onwards. The Options panel in Lightwave lets you set the Content Directory, and this helps to overcome most of the problems you run into when you move a scene file from one computer to another, or share scene files over a network. Understanding how this works and using relative paths is the real key to Screamernet. We have just made Screamernet even more complicated by connecting computer systems with totally different operating systems to the same network.

If you sit back and look at both your PC screen and Amiga screen now that you have all your drives mounted to each other, the problem that you will have to solve should be obvious to you. Well, maybe not. After all, I said this was the part that most people have trouble with.

On your PC, you have a drive V:\, which is really your Amiga drive with Lightwave on it. On your Amiga Workbench screen, you have a drive icon named N, which is the PC drive with Lightwave on it. Even if all you have are PC’s on your network, you’ll probably have the same problem. The ‘host’ computer with Lightwave on it will have Lightwave on drive D:\ perhaps, but the other systems can’t use that drive letter because it’s already in use by their own internal drive D:\, so they might end up with this drive getting mapped as drive E:\, for example.

It is absolutely imperative that all systems can see the same drives and that the exact same path and drive letters are used to access the files from all the systems on the network, or Screamernet won’t work properly.

In addition to this problem, several letters are permanently used by the Amiga operating system, and cannot be used at all if there is an Amiga on the network without screwing up the Amiga operating system. The letters that cannot be used if you have an Amiga on the network are C:, S:, L:, and T:. Fortunately, there is an easy way to get around this dilemma.

With Windows, you can share your drives so others can mount them. Other Windows systems should be set to map your D:\ drive as their drive N:\. The problem here is that the other systems will expect to load Lightwave files from their Drive N:\, but your ‘host’ computer expects to find Lightwave on Drive D:\. You need to fool your ‘host’ system into expecting Lightwave to be on Drive N:\ also. If you have Windows NT, you can do this by selecting your own Drive D:\ in the File Manager, and using the ‘Connect Network Drive’ option to map your own Drive D:\ as Drive N:\. If you open either drive, you will see that it is the same drive. You have just fooled Windows into thinking that you really have a Drive N:\. You cannot ‘Map Network Drive’ to yourself with Windows 95, but you can achieve the same effect by using the subst command. Open the MS-DOS Prompt program, and enter the command subst N: D:\ and hit Enter. When you open the Explorer, you’ll see that you now have a drive N: listed with your other drives, and it’s identical to drive D:\. You’ve just fooled Windows 95 in the same way.

If you set your Content Directory in Lightwave to N:\NewTek\, all of your systems will now look for (and find) Lightwave and all the Scene and Object files on the same PC drive, regardless of where they are on the network. If you edit your lw.cfg file and change all the occurrences of D:\ to N:\ where your plugins are defined, all your Windows machines will be able to find your plugins, too. If you make your SN\Command directory in N:\, and use drive N:\ instead of drive S:\ as the example is written in the Lightwave manual, everything will work properly. The example in the Lightwave manual is correct, it just doesn’t go into enough detail on how to make all your systems ‘see’ the same path to all of the Lightwave files. However, the example in the Lightwave manual is not recommended if you are running Screamernet on an Amiga, because S: is a reserved directory for the Amiga operating system. This is why I had you use drive N:\ instead.

If you set the Content Directory to N:Newtek in your Amiga Lightwave, the Amiga will use the exact same scene files and image data that your Windows system(s) do, located on your D:\ drive. Be careful if you edit your Amiga lw.cfg file, though. You MUST leave the definitions on where to find the plugins to point to your Amiga drive, and NOT the N:\ drive. Change the paths for your Amiga plugins to the FULL Amiga path of DH1:NewTek/Plugins/Layout/etc if they are not already listed that way. If you change the plugin paths to N:, your Amiga will try to load the Intel plugins from your PC, and they won’t work. Any time that you have mixed computer systems on a Screamernet network, you have to be very careful with the path definitions to your plugins to be sure that they are loading the proper plugins. You want all your systems to use the same Content directory, but only systems of the same CPU type can share their plugins. If you have a plugin for Intel Lightwave, you must also purchase the same plugin for DEC Alpha and Amiga, if you also have those platforms involved in a Screamernet render session.

Another ‘feature’ of Lightwave rears it’s head here, and must be addressed. When you set your ‘Save RGB Images’ option to a certain filetype, such as JPEG, Lightwave does not save the instructions to save your files as ‘JPEG’ in the scene file. It uses a number to refer to the filetype. The actual command that you will see at the end of the scene file will say ‘RGBImageFormat 8’ if you have your scene set to save JPEG images. The number 8 refers to the position that ‘JPEG’ occupies in the drop-down list when you click on the ‘RGB Image Format’ button in the ‘Record’ panel. Lightwave actually doesn’t know that you selected JPEG, it will just use the 9^th HIIP saver that is defined in your lw.cfg file. (The first item in the list is 0, so an item number of 8 is the 9^th item listed). You must be extremely careful that all of your systems have the saver modules defined in the same order, or you will get what I got when I first used a HIIP saver during a Screamernet session: Our PC rendered to JPEG, our Raptor3 rendered to JPEG, and the Amiga rendered to BMP. They were all rendering to ‘RGBImageFormat 8’, unfortunately on the Amiga, #8 was BMP, not JPEG.

If all you have are Windows systems, you’re ready to start up and use Screamernet. Unfortunately, a couple of bugs in Amiga Lightwave Screamernet 4.0 will give you some grief when it’s used in a Screamernet network where the other systems are Lightwave for Windows. Lightwave automatically translates the forward and backward slashes in pathnames if you take a scene file created on a PC and load it into Amiga Lightwave or a scene file created on the Amiga but loaded into the PC Lightwave. The Content Directory on your PC’s is N:\NewTek\ and your objects will load from N:\NewTek\Objects. On the Amiga, the Content Directory is N:NewTek/ and your objects will load from N:NewTek/Objects. Notice that the PC uses backwards slashes (\), and the Amiga uses forward slashes (/) in the pathnames. Lightwave and Screamernet will automatically translate a \ to / and vice-versa as required. If you tell Screamernet to save your rendered images in N:\jonesproject\, the Amiga version of Screamernet will translate this to N:/jonesproject/, and it won’t work. The slash immediately following the colon is invalid in AmigaDOS, whether it is a forwards or backwards slash. The Amiga will happily render the frames, but will not save anything. There is, as usual, a workaround for this.

When you have a multi-platform Screamernet network, always render to your Content Directory, and things will work OK, because you aren’t using any drive letters at all in the ‘save to’ path. If you make the directory for your rendered frames inside of the Content Directory, all your systems will find that directory with no problems. This is because they are all using a relative path instead of a fully-defined path, and there aren’t any drive letters being used. For example, you would make a directory called ‘jonesproject’ inside your N:\NewTek directory. Load the scene and set it to save the output images to jonesproject/framename.xxx. Since there is no drive name, only the directory path is used in your scene file, and both the Amiga and PC will handle this with no troubles.

You also won’t be able to use any of the HIIP saver modules when you have multi-platform Screamernet, due to another bug involving the HIIP savers. The scene file is a text file, and the Amiga saves scene files with only a linefeed character at the end to indicate the end of each line. PC’s use a carriage return character followed by a linefeed character. Lightwave translates this automatically when you cross-platform load scene files, but the HIIP savers do not. If you save the scene file from Amiga Lightwave set to save frames as JPEG for example, the Intel and Alpha HIIP savers will crash Screamernet with a Windows GPF failure when they go to save the very first frame.

If you save the scene file from Windows Lightwave set to use a HIIP saver, the Amiga Screamernet will again happily render the frames, but will not save anything. This only affects Screamernet and the HIIP savers, not Lightwave itself. If you use only the first two image options of either .iff or .tga, Lightwave and Screamernet will use their own internal image saver modules, and will have no problems in this regard. If you manually edit the scene file and add or remove the offending carriage returns as required and keep the Content Directory separate between platforms, each platform will be able load a working version of the scene file. This will also work, but require you to copy all of your content on the other systems, and your chances of missing a crucial object or texture file when setting this up skyrocket. If you are using Screamernet multi-platform, stick to the built-in image saving functions of either IFF or TGA.

OK, ready to give this all a try? Here’s the last final steps to start up a successful Screamernet session.

Make a directory of N:\SN\Command on your PC. Make a directory of N:\Newtek\Frames on your PC.

Start Lightwave on your PC and make sure that the Content Directory is set to N:\NewTek and that the Screamernet Command Directory is set to N:\SN\Command. Exit and shut down Lightwave to save the lw.cfg file and then re-start Lightwave again.

Load the intended scene file. It MUST load up with no errors or drive searching directly from your Content Directory. Set your Save RGB Images to Frames\outname. ‘outname’ can be any name for your frames that you wish, but do not use spaces in the filename or directory name. Screamernet does not like spaces in any of it’s filenames or directory names. Set the type of images to save as either IFF or TGA. Save this scene file.

Load up Lightwave on the Amiga and also make sure that the Content Directory is set to N:NewTek and that the Screamernet Command Directory is set to N:SN/Command. Load the scene file that you just saved on the PC to make sure that your Amiga can find all the scene elements. Shut down Lightwave on the Amiga to save the lw.cfg file.

On the Amiga we will assume that your Lightwave or Toaster software is located on drive DH1: Open a shell on the Amiga and type:

CD DH1:Newtek/Programs

lwsn.fp -2 N:SN/Command/job1 N:SN/Command/ack1

Wait a second or two, and you should see a message of "Can’t open N:SN/Command/job1". This is normal, and the message will repeat itself every few seconds.

On the PC, open the MS-DOS Prompt program and type:

N:\

CD \NewTek\Programs

lwsn.exe -2 N:\SN\Command\job2 N:\SN\Command\ack2

If you have more computer systems than just these two, repeat the above, but make the next system use job3 and ack3, the next after that job4 and ack4, etc. But keep the rest of the command structure the same.

Wait a second or two, and you will see the same "Can’t open N:\SN\Command\job2" message. This is also normal.

Flip back to the Lightwave screen and open the Screamernet panel. Set the Maximum CPU option to 2, and click on the ‘Screamer Init’ button. After a brief delay, it should tell you that it found 2 Screamernet CPUs. Click on Add Scene to List, select your scene file, and then select ‘Screamer Render’, and they should both start rendering. Look at the open shells where you typed your commands, and you should see a stream of status messages telling you what each system is currently doing. Check with a disk utility to make sure they are all actually saving something.

If something goes wrong, go back to the Lightwave Screamernet control panel, click on the screen to make sure it has the ‘focus’, and hit the escape key to stop the Screamernet process. Go to the computer that is having the problem, bring the command shell to the front and type a CTRL/C to stop that particular Screamernet node. Check to see that you have the proper paths set in your command line and try again.

Once you get this all working, automate the process a bit by typing the Screamernet commands for that system in a text editor and save it on each system. To avoid confusion, I recommend saving with a different name each time that includes the Screamernet node number, such as "StartScreamer1.bat", "StartScreamer2.bat", etc. Both Windows and AmigaDOS allow attaching an icon to this file, so that the next time you want to run Screamernet, you can start it all up just by clicking on it’s icon.

You can use Screamernet to batch render multiple scene files by just clicking on the Add Scene to List button multiple times. This is great if you have a couple of smaller scene files that would render overnight or maybe some longer ones to render over the weekend while you’re away. This sure beats coming back to the office in 6 hours just to load up the next scene to render. One limitation of this is that all of the scenes to be rendered must be within the same Content Directory path. The Lightwave manual says that you can tell Screamernet to batch render up to 16 scene files at a time, but the scene counter in the Screamernet control panel goes up to 100. Go figure. Maybe that’s coming in Lightwave 6.0.

There you have it, networking and Screamernet in a nutshell, albeit rather lengthy. In addition to being able to double, triple, quadruple or more to your rendering speeds by simply adding more systems on your network, you will also save a ton of time the next time that you want to use a video clip sequence in Lightwave from your Flyer or Perception, and won’t even have to leave your comfy chair to go and fetch all those frames.

INET-225, INET-NSFd, and AmiTCP v4.x: Available at Amiga software dealers. (Commercial software).

Also see the Interworks site at http://www.iworks.com.

Amiga Samba Server: Aminet Internet archive sites, /pub/aminet/comm/net/samba-1.9.15p8.lha.

Ixemul software required for Samba: Aminet Internet archive sites, /pub/aminet/dev/gcc/ixemul-040fpu.lha, or /pub/aminet/dev/gcc/ixemul-020fpu.lha, depending on your CPU.

A web-browsable access to Aminet can be found at: http://www.germany.animet.org/aninet/.

Sample Aminet Internet FTP archive site: ftp.netnet.net.

All of the non-commercial Amiga software mentioned here as well as the TropicNFS software is also available at ftp.mt-inc.com, /pub/amiga/ and /pub/windows/ as well as on the World Wide Web at http://www.mt-inc.com/amiganet.htm.

TropicNFS: http://www.webcit.com/br/tropic/. (Win95 and WinNT Intel-only NFS Server).