david@uhccux.uhcc.hawaii.edu (David Lassner) (06/25/89)
Page 10-1 of the A/UX 1.1 Network System Administration reference says "Because of the high processing requirements of both AppleTalk and the A/UX multitasking OS, AppleTalk under A/UX requires a coprocessing card. Contact your Apple representative for a list of cards that are available from various vendors." It goes on to give instructions for installing the AppleTalk card. Is this for real? Do we really need a card to print to an AppleTalked LaserWriter and if so, who makes them? -- David Lassner, University of Hawaii Computing Center INTERNET: david@uhccux.uhcc.hawaii.edu BITNET: david@uhccux Voice: 808/948-7351 FAX: 808/946-5848
liam@cs.qmc.ac.uk (William Roberts) (07/04/89)
In article <4170@uhccux.uhcc.hawaii.edu> david@uhccux.uhcc.hawaii.edu (David Lassner) writes: >Page 10-1 of the A/UX 1.1 Network System Administration reference >says "Because of the high processing requirements of both AppleTalk >and the A/UX multitasking OS, AppleTalk under A/UX requires a coprocessing >card. ... >Is this for real? Do we really need a card to print to an AppleTalked >LaserWriter Yes, it's for real. The problems is to do with interrupt service times and the very feeble hardware provided for the LocalTalk interface. Basically that thing has a three byte buffer inside it, so you have to pull those bytes out very, very quickly if you don't want to lose packets. I did hear something about AT&T requiring a minimum interrupt service time from anything to be called "UNIX" and it being very hard to meet this with the Mac II hardware. They could use a newer version of the chip (bigger buffer), but the current trend at Apple seems to be using add-in hardware for comms. In particular, they are keen on co-processor cards, i.e. where you make the card do some of the work and so off-load processing effort from the Mac II. > and if so, who makes them? The manual entry you quoted says it all: > Contact your Apple representative for a list of cards that are >available from various vendors." I admit it is rather bizarre (it can talk LocalTalk when it's a MacOS machine, what happened under A/UX?) but there does seem to be a reason for it. At least your Apple representative is likely to tell you ALL of the vendors who make such cards :-) -- William Roberts ARPA: liam@cs.qmc.ac.uk Queen Mary College UUCP: liam@qmc-cs.UUCP AppleLink: UK0087 190 Mile End Road Tel: 01-975 5250 LONDON, E1 4NS, UK Fax: 01-981 7517
jlh@stech.UUCP (Jan Harrington) (07/04/89)
in article <1147@sequent.cs.qmc.ac.uk>, liam@cs.qmc.ac.uk (William Roberts) says: >>Page 10-1 of the A/UX 1.1 Network System Administration reference >>says "Because of the high processing requirements of both AppleTalk >>and the A/UX multitasking OS, AppleTalk under A/UX requires a coprocessing >>card. ... >>Is this for real? Do we really need a card to print to an AppleTalked >>LaserWriter > > Yes, it's for real. The problems is to do with interrupt service times > and the very feeble hardware provided for the LocalTalk > interface. Basically that thing has a three byte buffer inside >> and if so, who makes them? > > The manual entry you quoted says it all: > While finishing writing my A/UX book, I've been using a CommCard from SuperMac Technology. (The nice folks there loaned it to me). It has four serial ports and can be used either for four serial connections OR one AppleTalk connection. It retails for about $1000. It has nice installation software (rebuilds the kernel for AppleTalk, etc.). Jan Harrington Scholastech Telecommunications husc6!stech!jlh or allegra!stech!jlh ************************************************************************* Miscellaneous profundidity: "No matter where you go, there you are..." Buckaroo Banzai *************************************************************************