AHA-284x Family
Common Questions and Answers
Doc. # 39140


Q. When I plug my AHA-2842VL into my system, the system hangs 
   on boot up.  Why?
A. The AHA-2842VL is a bus mastering device and requires that the VL 
   slot support full 32-bit bus mastering.  Most VL Bus systems have 
   either slave slots and/or master slots.  The adapter must be inserted 
   into a master slot.  If you are not sure if the system supports bus 
   mastering or if you have a master slot, contact the system 
   manufacturer.

   Additionally, the slot that the AHA-2842VL card is inserted into must 
   be a 5 Volt slot that operates at 33 MHz or less. The VL Bus speed is 
   typically set through a jumper on the motherboard. It should be set in 
   the <=33 MHz (less than or equal to 33 MHz) position.
   The motherboard should be set for write-through caching if you are 
   using a 2842VL. This may be set in the motherboard's CMOS setup 
   utility or it may be configured via a jumper on the motherboard. If 
   there is both a CMOS setting and a jumper, be sure they are both set 
   the same way.


Q. I have just upgraded my CPU to a faster speed, such as a 486DX2-
   80, 486DX4-100 or 486DX4-120 processor, and my system now 
   either locks up with the card installed or won't boot from the SCSI 
   hard drive. The adapter and drive worked successfully prior to the 
   upgrade. Why is this?
A. Most likely there is an DMA or other timing discrepancy between the 
   AHA-284x(A) adapter and the VL local bus. The AHA-284x(A) 
   adapter has been tested to run successfully on the VL Bus at speeds of 
   up to 33 MHz. These CPUs can increase the Bus speed beyond 33 
   MHz. Above this 33 MHz speed, variations in motherboard, chipset or 
   CPU design may cause our adapter to function intermittently or to fail. 
   In some cases this problem can be resolved and we offer these 
   suggestions:

     1. The motherboard may have jumpers that govern the VL Bus speed. 
        Be sure that the VL Bus speed jumper is set in the <=33 MHz (less 
        than or equal to 33 MHz) position. This may also be set in the 
        motherboard's CMOS setup.

     2. In the CMOS setup, you can disable the CPU external cache, 
        change the caching method to write-through instead of write-back. 
        Also, Jumper J5 controls write-back cache compatibility. Try placing a 
        jumper on this jumper block.

     3. The Internal cache on some CPUs may cause this hang as well. 
        Disabling the CPU's internal cache may help.

     4. Reducing the CPU speed may be necessary to allow the AHA-
        284x(A) adapter to function reliably.

     5. Disable the system's turbo setting during the boot-up sequence. 
        Then re-enable the turbo setting after the system has booted.

     6. Of all the various  CPU chips on the market, the Intel 486DX series 
        of CPUs seem to be the most compatible with our adapter.


Q. I have a SLC processor-based system, will the AHA-2842VL 
   work?
A. The AHA-2842VL will not run successfully in the "SLC" 
   processor based systems as they use 16- bit rather than 32-bit 
   architecture at the VL Bus.  The AHA-2842A will operate in both 
   the 32-bit and the 16-bit VL Bus architecture.


Q. When I press <ctrl A> to run the SCSI-Select utility, my computer 
   tells me "Unable to execute SCSI-Select". How do I fix this?
A. The cache on your motherboard may be set to allow write-back 
   caching. Install a jumper on jumper block J5 of the AHA-284x(A) 
   adapter. This will enable support for the write-back caching method.


Q. When should the BIOS on the AHA-284x(A) SCSI Host Adapter 
   be disabled?
A. If you don't have a bootable device, such as a hard drive, then the 
   BIOS should be disabled. This is done through the SCSI-Select utility 
   <ctrl A> at boot up, in the Advanced configuration.


Q. When running Qualitas 386MAX memory manager software on 
   ISA or VL systems with an AHA-284x host adapter, the system 
   hangs when booting up.
A. Do not allow 386MAX to load during boot up.  Then include the key 
   NOIOWRAP on the 386MAX command line.  This will allow you to 
   boot with 386MAX loaded.


Q. When trying to install a hard drive, it isn't recognized, it hangs or 
   is getting erratic behavior.
A. Some drives are not capable of operating properly at a 10MB/second 
   synchronous transfer rate.  Lower the synchronous transfer rate to 
   5MB/second and see if the device works properly.  This can be 
   modified through SCSI Select <ctrl A> at boot up, in the SCSI device 
   configuration.

   This can also be related to termination and cabling. Be sure that your 
   cables are connected firmly and that they are not reversed.  Be sure 
   that the last device on each end of the SCSI bus are terminated 
   properly, and that devices in the middle are not terminated. See your 
   User's Guide for further information on termination.


Q. Will my floppy cable-based tape drive give me dependable 
   backups and restores of my AHA-284x(A) VL-based SCSI devices?
A. Not necessarily.  Due to the significant transfer speed differential 
   between these two technologies most floppy-based tape drives tend to 
   get "lost" trying to keep up with the off-loading speed of the VL bus 
   devices.  There is no approved scheme for slowing down the VL 
   devices enough so to insure dependable transfers to the floppy-based 
   tape drives.  Use of a compliant SCSI tape drive connected to the 
   AHA-284x(A)VL card is recommend.


Q. What is the Adaptec BBS telephone number?
A. The number in the US is 408-945-7727. Most files are also available 
   on our World Wide Web site at http://www.adaptec.com. Additionally, 
   they are available on Compuserve (go adaptec) and Microsoft  
   Network.

Q. Where can I find Netware 3.x or 4.x drivers for my AHA-284x(A) 
   SCSI Host Adapter?
A. The driver for the AHA-248x(A) is available on our BBS under the 
   file name NW31X.EXE for Netware v3.1x or NW4X.EXE for Netware 
   v4.x. Please run the file to decompress the contents, then read the 
   included README.TXT file before installing. NOTE: There is no 
   support available for this adapter under Netware v2.x.


OS/2

Q. Does the AHA-2842VL support OS/2 v1.3?
A. There is no driver support for the AHA-2842 under OS/2 v1.3.


Q. Where can I get drivers for the AHA-2842VL or AHA-284x(A) for 
   OS/2 v2.x?
A. The driver for the AHA-248x(A) is available on our BBS under the 
   file name 7700OS2.EXE. Please run the file to decompress the 
   contents, then read the included README.TXT file before installing.


WIN NT

Q. I have an AHA-2842VL SCSI host adapter.  Where can I get the 
   WIN NT drivers for this SCSI host adapter?
A. The driver for the AHA-2842VL is on the BBS under the filename 
   7700WNT.EXE.  Please run the file to decompress the contents, then 
   read the included README.TXT file before installing.

Q. I have just purchased a AHA-284x(A) host adapter and am trying 
   to install it under Win NT v3.5 or v3.51 but the driver isn't there. 
   Where can I get the driver for this adapter?

A. The driver for the AHA-284x(A) is embedded in the Windows NT 
   Operating System for v3.5 or v3.51.  The name of the driver is 
   misleading.  It is called ARROW.SYS.


SCO UNIX 

Q. Where do I obtain the SCO UNIX 3.2.4 drivers for the AHA-
   2842VL?
A. The drivers are in the 7700 Family Manager Set for SCO 
   UNIXWARE.  To order the 7700 Family Manager Set, please call 
   (800) 442-7224 or (408) 957-7274 from outside the United States and 
   Canada. In addition, these drivers are available on our BBS under the 
   file name 7700UNIX.EXE. Please run the file to decompress the 
   contents, then read the included README.TXT file before installing.

Revised on 4/4/96