CAP(8)

NAME
CAP - Columbia AppleTalk Package for Unix

DESCRIPTION
CAP implements a portion of Apple Computer's AppleTalk protocols on a variety of UNIX hosts. There are two distinct link access delivery mechanisms for CAP: IPTalk and Ethertalk.

IPTalk is the traditional CAP configuration. It encapsulates Appletalk in UDP/IP packets, thus allowing you to install CAP on any system that supports IP. It requires special Appletalk bridges that understand the IPTalk encapsulation. Suitable candidates are the Kinetics/Shiva FastPath, Webster MultiPort Gateway, Cayman GatorBox or Stanford University's Seagate box.

Ethertalk is the standard Apple way of using Appletalk on Ethernet. The three methods of producing EtherTalk packets with CAP are:
"Native EtherTalk" using packet filters built on the Stanford ENET model. Currently available for NIT or ENET on SunOS and the ULTRIX Packet Filter only. Native EtherTalk is both Phase 1 and Phase 2 compatible.

"Kernel AppleTalk" for systems that provide appropriate kernel AppleTalk support at the DDP level or where the 'netatalk-1.2' package from the University of Michingan is installed. Currently supports Phase 1 only.

"UAB" is the Unix Appletalk Bridge. The main use for UAB is as a bridge between two or more ethernet interfaces but it can also be used to provide access to CAP services. With UAB, EtherTalk packets pass through a single gateway process which places fewer restrictions on the network interface. UAB currently runs under SunOS, ULTRIX, SGI IRIX, SONY NEWS and (soon) HP-UX. UAB is currently Phase 1 compatible only.

CAP routines are structured, for the most part, the same as the Apple routines described in "Inside AppleTalk" and "Inside LaserWriter." Refer to the Apple documents and the procedure comments for a complete description of the routines and how to call them.

Currently the AppleTalk protocols supported by CAP are:
AppleTalk Transaction Protocol (ATP)
Name Binding Protocol (NBP)
Printer Access Protocol (PAP)
AppleTalk Session Protocol (ASP)
AppleTalk Filing Protocol (AFP) client side
In addition, the Datagram Delivery Protocol (DDP) and Zone Information Protocol (ZIP) are partially available. The structure of the Internet Appletalk Bridge software makes it impossible to provide full DDP service for IPTalk. Only the Get Zone List ATP ZIP command is implemented for ZIP.

IPTalk CAP, is of course, highly dependent upon the availability of a Ethernet to Appletalk gateway which we term an Internet Appletalk Bridge. Currently, CAP is based upon the KIP revision of the UDP code as done by Bill Croft of SUMEX at Stanford University. The K-STAR code, version 7.0 or higher, for the Shiva FastPath is compatible as is any version of 'Megan', the gateway code for the Webster MultiPort Gateway.

Three main CAP applications are available:

papif
    acts as a line printer input filter spooling from a unix host to a LaserWriter. See papif(8) for more information.

lwsrv
    offloads spooling to the LaserWriter from the MacIntosh to a Unix host. See lwsrv(8) for more information.

aufs
    is an AppleTalk Filing Protocol unix file server (AppleShare compatible). See AUFS(1) and AUFS(8) for more information.

In addition, there are a number of sample programs. These are included strictly to point out some of the functionality made available by CAP.

lwpr
    is a simple program which allows printing from a CAP host to a LaserWriter. See atprint(1) for more information.

tlw accesses the interactive mode of the LaserWriter, known as the executive. See atprint(1) for more information.

isrv, iwpr
    spool from and print to an AppleTalk ImageWriter. See atprint(1) for more information.

atlook, atlooklws, atpinger
    lookup Appletalk names. See atlook(1) for more information.

AUTHOR
Charlie C. Kim, User Services, Columbia University Center for Computing Activites and Bill Schilit, Computer Science Department, Columbia University. Contributions from Bill Croft, Stanford University and Dan Tappan of Bolt, Bernak, and Newman.

NOTES
Bill Croft's original work in this area provided the inspiration for CAP.

Unfortunately, the interfaces for CAP have diverged some from the Apple specifications (additional features, some code was written before Apple released their specifications, etc). Most of the differences are documented in the "doc" directory that comes with CAP.

The ZIP functions work only with revision 1/88 or later of KIP.

SEE ALSO
aarpd(8), atis(8), AUFS(1), AUFS(8), papif(8), lwsrv(8), atprint(1), atlook(1), CAP(3)