RN BI resistor network 899-5, R220/330 

F1 - From Peter- The fuses are Schurter (Switzerland) microfuses of the MSF-125 series, order no. 0034.9875 - a single package is 10 pieces at 125V / 1.6A, rated "quick acting F". Schurter has an internet page with product catalogues in .PDF at www.schurter.ch (Ed. A PTC resistor might work here as well)

Transfer rates
        Up to 8 MBytes/sec bus master DMA on the Micro Channel bus 
        5 MB/s synchronous burst or 2 MB/s asynchronous burst on the SCSI bus 

RAID Support
The AHA-164x supports RAID Level 0, 1, and 5 with the help of third party software. Ed. Whose software? 

W95 and DMA Channels
   It seems as if W95 has the choices of DMA Channels 5, 6, and 7 available. You may have to go into the System Programs (a.k.a. Setup) and change the Arbitration Level to one that W95 is looking for. 

No SCSI BIOS Installed
1.   The AHA1640 says no SCSI BIOS installed. The chips are there on the card. 

The Bios is installed under following circumstances: 
- no "drive C: " (Hex-80 device) previously installed 
- drivesize is 1GB or below 
- BIOS is enabled under the machine setup and on a valid adress 

2. I can't get it to boot a HDD which boots fine form a Future Domain. 
     If the drive is over 1GB and / or low-level formatted with a different translation schem it will not be recognized anyway. The Adaptec Boot BIOS is "old fashioned" and has a 1GB-limit. 
   It is principially the same as used on the ISA AHA-1540B (not -C or -CF) and has no CTRL-A support and uses the DOS-compatible HD translation, which is a bit "register-width challenged". 
   You need to LL-Format the drive with Adaptecs SCSIFMT ... which requires a boot disk with the ASPI4DOS.SYS to have the drive under ASPI-Manager control. The ASPI Manager is capable to handle drives over 1GB - the Boot-Bios isn't. 

   Ed. IML systems depend on the Int4b function to perform the Initial Microcode Load. With any non-IBM SCSI adapter installed, the non-IBM SCSI adapter will be scanned first (all of them have a lower I/O address than the IBM SCSI adapters). Even _IF_ there is a bootable device on the AHA-1640, it CANNOT perform the IML. Since the IML is not completed, the system cannot scan for the IBM SCSI adapter for the IML information. Result: System hang.

Nihavent Longa sounds off with:
   They do - the Onboard Utility is accessed through the DOS debug, type 'debug' on the DOS prompt and then enter G=XXXX:6, replace XXXX by the segment value of the BIOS base address, for the default value use G=DC00:6, you can then list installed SCSI devices and low-format any target/LUN.

   You can have multiple AHA-1640s in a system, as usual only one BIOS should be enabled. The BIOS will select as the boot device the host adapter with the lowest number physical slot among those having a 0 as the last digit of their I/O addreses (330h, 230h or 130h). If using auto-config, the adapter in the lowest slot will be selected as the boot adapter and assigned I/O address of 330h.

   If you want to use another adapter as the boot adapter, all adapters in a lower numbered slot than the boot adapter should have a 4 as the last digit in their I/O addresses, i.e. 334h, 234h or 134h. Again, only one adapter should have its BIOS enabled.

Adapter BIOS
   Memory location of the adapter's BIOS ROM. Note, if two AHA-1640 host adapters reside in the system, one of them must have its BIOS ROM disabled. 
      <DC000h>, D8000h, D4000h, D0000h, CC000h, C8000h, BIOS disablednameditem 

I/O Port Address
   I/O Port of the adapter 
      <330h>, 334h, 234h, 134h, 230h, 130h" 

Arbitration Level
   Selectes the DMA channel used to transfer data. 
      <Level_5>, Level_6, Level_7, Level_4, Level_3, Level_1, Level_0" 

Interrupt Level
   Interrupt channel used to report status. 
      <Int_15>, Int_14, Int_12, Int_11, Int_10, Int_9 

SCSI Address
     SCSI address of the host adapter 
      <Addr_7>, Addr_6, Addr_5, Addr_4, Addr_3, Addr_2, Addr_1, Addr_0 

Sync Xfer Started by AHA-1640 Yes/No
   Synchronous transfer on the SCSI bus will be started by the adapter if 'Yes'. 
     <Yes>, No 

SCSI Parity Checking On/Off
    The host adapter will check SCSI Parity if  'On' 
    <On>, Off 

Fairness On/Off
   Bus Arbitrations Fairness. This controls whether the adapter will release control of the bus when it has been using it exclusively. 
      <On>,Off