Arcnet networking system - old, slow but cheap and reliable, useful for small LANs and simple network sharing
Arcnet requires RG62 coaxial cable instead of the RG58 used on Ethernet systems
uses 93 ohm terminators opposed to the 50 ohm used by Ethernet
the Arcnet interface hybrid chip comes in two different versions, HCY 9058 for bus networks and HCY 9068 for star networks
the manual says the card uses a bus network layout with up to 256 nodes but many A2060s has 9068 hybrids for a star network layout allowing only four cards to be connected together
to solve this the HCY 9068 can be simply replaced with a HCY 9058 chip
interrupt driven (polled I/O) - one interrupt on the Amiga yields into a busy system
to reduce traffic the driver uses the Arcnet hardware's four buffer as a single FIFO buffer
the badly written driver (a2060.device) has some bugs in the FIFO buffer which results in lost packets and packet collisions - increased traffic on the Arcnet bus
manual says 2.5 Mbit/s (300 kB/s) transfer speed but only max 100 kB/s is achievable
can be ordered with no CPU or with a new or a recycled 68060
memory
four 72 pin SIMM sockets accept 128 MB RAM
four 64 pin GVP SIMM sockets for backward compatibility
the 72 pin sockets support 4, 8, 16 or 32 MB SIMMs, the GVP sockets support 4 or 16 MB SIMMs
each 64 pin slot is linked directly to a 72 pin one - only one of them can be used at the same time
cannot mix 4 or 16 MB GVP SIMMs
cannot mix single or double sided 72 pin SIMMs
a double sided 72 pin SIMM rules out two GVP SIMM sockets
supports burst RAM access when SIMMs are installed in pairs
selectable RAM access speed 60-80 ns
Fast SCSI 2 controller
10 MB/s max transfer speed
50 pin internal header
50 pin external high density connector
optional 3.5" hard disk mounting kit
active SCSI termination can be disabled with jumper
the tekscsi2.device is not NSD compliant, it autoboots FFS partitions only - it looks for filesystems in the Kickstart ROM, but it does not care about filesystems loaded into the RDB area
notes
68000 fallback mode with access to the SCSI controller and memory expansion
jumper settings
JR1 -
burst mode: ON - enabled
JR2 -
RAM speed: OFF - faster access time
JR3 -
burst write: ON - enabled
JR4 -
burst read: ON - enabled
JR5 -
GVP SIMM: ON - 16 MB, OFF - 4 MB
JR6 -
72 pin SIMM: ON - double sided, OFF - single sided
JR7 -
reserved
JR8 -
refresh: ON - 4k, OFF - 2k or 4k
J1 -
CPU power: 1-2 - 5V, 2-3 - 3.3 V
J2 -
CPU clock: 1-2 - 68040, 2-3 - 68060
J3 -
clock: OFF - enabled
J4 -
68000 mode: OFF - enabled
J5 -
DTACK pull-up: OFF - enabled
J6 -
active SCSI termination: OFF - enabled
J7 -
interrupt pending: ON - DMA backoffs, OFF - DMA ignores interrupt