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                                                           

