usr/share/man/cat4/tahoe/ace.0

ACE(4)           BSD Programmer's Manual (Tahoe Architecture)           ACE(4)

N\bNA\bAM\bME\bE
     a\bac\bce\be - ACC 10 Mb/s Ethernet interface

S\bSY\bYN\bNO\bOP\bPS\bSI\bIS\bS
     d\bde\bev\bvi\bic\bce\be a\bac\bce\be0\b0 a\bat\bt v\bvb\bba\ba?\b? c\bcs\bsr\br 0\b0x\bxf\bff\bff\bff\bf0\b00\b00\b00\b0 f\bfl\bla\bag\bgs\bs 0\b0x\bxf\bff\bff\bf8\b80\b00\b00\b00\b0 v\bve\bec\bct\bto\bor\br a\bac\bce\bec\bci\bin\bnt\bt
           a\bac\bce\ber\bri\bin\bnt\bt

D\bDE\bES\bSC\bCR\bRI\bIP\bPT\bTI\bIO\bON\bN
     The a\bac\bce\be interface provides access to a 10 Mb/s Ethernet network through
     an ACC controller.

     The hardware has 32 kilobytes of dual-ported memory on the VERSAbus. This
     memory is used for internal buffering by the board, and the interface
     code reads the buffer contents directly through the VERSAbus. The address
     of this memory is given in the _\bf_\bl_\ba_\bg_\bs field in the configuration file.

     Each of the host's network addresses is specified at boot time with an
     SIOCSIFADDR ioctl(2).  The a\bac\bce\be interface employs the address resolution
     protocol described in arp(4) to dynamically map between Internet and Eth-
     ernet addresses on the local network.

     The interface normally tries to use a ``trailer'' encapsulation to mini-
     mize copying data on input and output.  The use of trailers is negotiated
     with ARP. This negotiation may be disabled, on a per-interface basis, by
     setting the IFF_NOTRAILERS flag with an SIOCSIFFLAGS ioctl.

     The device implements an exponential backoff algorithm when notified of a
     collision on the cable.  This algorithm utilizes a table of random num-
     bers setup by the system at boot time.  The delay is done in the con-
     troller.

D\bDI\bIA\bAG\bGN\bNO\bOS\bST\bTI\bIC\bCS\bS
     a\bac\bce\be%\b%d\bd:\b: s\bst\btr\bra\bay\by x\bxm\bmi\bit\bt i\bin\bnt\bte\ber\brr\bru\bup\bpt\bt,\b, x\bxn\bnc\bct\bt %\b%d\bd.\b.  An unexpected transmission com-
     plete interrupt was received; the interrupt is ignored.

     a\bac\bce\be%\b%d\bd:\b: c\bca\ban\bn'\b't\bt h\bha\ban\bnd\bdl\ble\be a\baf\bf%\b%d\bd.\b.  The interface was handed a message with ad-
     dresses formatted in an unsuitable address family; the packet was
     dropped.

S\bSE\bEE\bE A\bAL\bLS\bSO\bO
     intro(4),  inet(4),  arp(4)

H\bHI\bIS\bST\bTO\bOR\bRY\bY
     The a\bac\bce\be driver appeared in 4.3BSD-Tahoe.

B\bBU\bUG\bGS\bS
     The hardware is not capable of talking to itself.  The software imple-
     ments local sending and broadcast by sending such packets to the loop in-
     terface.  This is a kludge.

     The device doesn't autoconfigure its interrupt vector; it is set at 0x90
     + eight times the unit number.

4.2 Berkeley Distribution        June 5, 1993                                1