Adaptec 2940U - AHA Storage Controller Ultra SCSI 20... User manual

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Introduction
The Adaptec AHA®-2940Ultra and AHA-2940Ultra
Wide PCI-to-Fast SCSI host adapters provide a pow-
erful multitasking interface between your com-
puter’s PCI bus and SCSI devices (disk drives,
CD-ROM drives, scanners, tape backups, removable
media drives, etc.). Collectively, both host adapters
are referred to as the AHA-2940Ultra/2940Ultra
Wide. The following figures show the major compo-
nents on the AHA-2940Ultra and AHA-2940Ultra
Wide.
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Adaptec AHA-2940 Ultra
50-pin 8-bit Internal
SCSI Connector
Host
Adapter
LED
AIC-78xx SCSI Protocol Chip
50-pin 8-bit
External
SCSI
Connector
Host Adapter
BIOS LED Connector
Adaptec AHA-2940 Ultra Wide
50-pin 8-bit Internal
SCSI Connector
Host
Adapter
LED
AIC-78xx SCSI Protocol Chip
68-pin 16-bit
External
SCSI
Connector
LED Connector
Host Adapter
BIOS
68-pin 16-bit
Internal SCSI
Connector

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Installing the Host Adapter
Follow these instructions to install the host adapter:
1
Turn OFF power to the computer and peripheral
devices and disconnect the power cords.
2
Remove the cover from the computer case.
3
Locate an unused 32-bit PCI expansion slot (the
slot must support Bus Master data transfers);
unscrew and remove the metal bracket that covers
the card-slot opening. (Save the screw to use when
securing the host adapter in your computer.)
PCI slots are shorter than ISA or EISA slots and
are typically white. One of these may be a shared
slot into which you can insert either an ISA/EISA
board or a PCI board.
4
Insert the host adapter in the PCI expansion slot.
Press it down firmly so that the contacts are
securely seated in the slot.
5
When the host adapter is firmly seated in the
expansion slot, secure the metal bracket of the host
adapter with the screw you removed in step 3.
Do not replace the computer cover or reconnect your
computer and peripherals to their power sources yet!
SCSI Configuration Guidelines
Before installing your SCSI devices, you should
understand the basic SCSI concepts described in this
section. The information will help you set up your
host adapter and devices so they function properly.
SCSI ID Numbers
Each device attached to the host adapter, as well as
the host adapter itself, must have a unique SCSI ID
number (0 to 7 for the AHA-2940Ultra, and 0 to 15 for
the AHA-2940Ultra Wide).
We recommend that you leave the host adapter set
to its default setting of SCSI ID 7. If you need to
change the host adapter SCSI ID, see Configuring the
Host Adapter on page 7. To change the SCSI ID on
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your hard disk and other SCSI devices, refer to the
device’s documentation.
The host adapter supports the SCSI Configured
AutoMatically (SCAM) protocol, which assigns SCSI
IDs dynamically and resolves SCSI ID conflicts auto-
matically at bootup. If your system includes SCSI
disk drives or other devices that support SCAM, you
do not need to manually assign SCSI IDs to these
devices. To enable SCAM support, see Configuring
the Host Adapter on page 7.
Most SCSI devices currently in use, however, do not
support SCAM. The SCSI IDs on these devices must
be set manually. To change the SCSI IDs on these
devices, refer to the device’s documentation.
Note:
If you plan to boot your computer
from a SCSI device attached to the host
adapter, set the Boot Target ID setting in the
SCSISelect utility to correspond to the SCSI
ID of the device you are booting from (see
Configuring the Host Adapter on page 7).
SCSI Terminators
To ensure reliable communication, the SCSI bus must
be properly terminated. Termination is controlled by
a set of electrical resistors, called terminators. Termi-
nators must be placed (or enabled) at the two
extreme ends of the SCSI bus. All devices that lie
between the ends must have their terminators
removed (or disabled).
Terminating the AHA-2940
Ultra
Termination on the AHA-2940Ultra itself is con-
trolled by software commands via the SCSISelect
utility. The default setting is Automatic, which works
like this:
■If the AHA-2940Ultra detects that a cable is con-
nected to either its internal or external SCSI con-
nector, then it enables its terminators (the
AHA-2940Ultra is at the end of the SCSI bus).

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■If the AHA-2940Ultra detects that a cable is con-
nected to both its internal and external SCSI con-
nector, then it disables its terminators (the
AHA-2940Ultra lies between the ends of the SCSI
bus).
We recommend that you leave the AHA-2940Ultra
set to its default setting of Automatic. If you want to
manually enable or disable the AHA-2940Ultra ter-
mination setting, see Configuring the Host Adapter on
page 7.
Terminating the AHA-2940
Ultra
Wide
Termination on the AHA-2940Ultra Wide itself is
controlled by software commands via the SCSISelect
utility. The default setting is set to Automatic.
We recommend that you leave the AHA-2940Ultra
Wide set to its default setting of Automatic. If you
want to manually set the AHA-2940Ultra Wide ter-
mination setting, see Configuring the Host Adapter on
page 7. The following table lists the termination set-
tings for manual configuration.
Terminating SCSI Devices
Read the device’s documentation to determine how
to enable or disable termination on your particular
SCSI device(s). On most internal SCSI devices the ter-
mination setting is controlled by a jumper or a
switch. On other internal SCSI devices you must
physically remove or install resistor module(s). On
most external SCSI devices, a terminating plug (a
resistor pack embedded in a small plug) is installed
or removed to control termination.
AHA-2940
Ultra
Wide Termination
Devices Connected to AHA-2940
Ultra
Wide Low High
68-pin internal connector only ON ON
68-pin external connector only ON ON
68-pin internal and 68-pin external connectors OFF OFF
50-pin internal connector only ON ON
50-pin and 68-pin internal connectors OFF ON
50-pin internal and 68-pin external connectors OFF ON

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Installing SCSI Devices
You can connect up to a total of seven internal and
external 8-bit SCSI devices to the AHA-2940Ultra, and
up to 15 devices (seven 8-bit internal and eight Wide
(16-bit) internal or external SCSI devices, or 15 Wide
internal and external SCSI devices) to the
AHA-2940Ultra Wide.
Note:
You may only use two of the
three connectors at any one time on the
AHA-2940Ultra Wide host adapter.
Choosing SCSI Cables
The cables required to connect SCSI devices are
determined by the type of devices you are installing,
as described in the following table.
If you purchased your AHA-2940Ultra/2940Ultra
Wide in an Adaptec kit, the kit includes an internal
SCSI cable that allows you to connect up to two
internal SCSI devices (the AHA-2940Ultra kit
includes a 50-pin internal SCSI cable, and the
AHA-2940Ultra Wide kit includes both a 50-pin and
a 68-pin internal SCSI cable). If you are connecting
more than two internal SCSI devices, you must
obtain an internal SCSI cable with enough connec-
tors to accommodate all of your devices.
Adaptec sells high-quality internal and external SCSI
cables. If your reseller does not stock these cables,
you can order them directly from Adaptec.
When Fast SCSI devices are connected to the host
adapter, the total length of all cables (internal and
SCSI Device Type AHA-2940
Ultra
AHA-2940
Ultra
Wide
8-bit Internal SCSI 50-pin internal
SCSI cable 50-pin internal SCSI cable
8-bit External SCSI 50-pin high-density
external SCSI cable —
16-bit Internal
Wide SCSI — 68-pin internal SCSI cable
16-bit External
Wide SCSI — 68-pin external SCSI cable
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external) must not exceed 3 meters (9.8 ft.) to ensure
reliable operation. If no Fast SCSI devices are con-
nected, the total length of all cables must not exceed
6 meters (19.7 ft). See your device’s documentation
to determine if it is a Fast SCSI device.
Connecting Internal SCSI Devices
If you are connecting internal SCSI devices, make
sure you have an internal SCSI cable with enough
connectors to accommodate all of your devices.
1
Prepare each SCSI device for installation; config-
ure the device SCSI ID and terminators (terminate
the last internal device attached to the cable). For
instructions, see the device’s documentation as
well as SCSI Configuration Guidelines on page 2.
2
Install the SCSI device in your computer. Refer to
your computer and device documentation for
instructions.
3
Plug the connector at one end of the internal SCSI
cable into the host adapter’s internal SCSI
connector.
Make sure the colored stripe on one side of the
cable is aligned with pin-1 of the host adapter’s
connector. Pin-1 of the connector is usually desig-
nated by a small triangle (▲), or a “1” on the
connector.
4
Plug the remaining connectors on the cable into
the connectors on the backs of the devices.
Make sure the colored stripe on the cable is
aligned with pin-1 of the device’s connector.
5
Connect a DC power cable (from your com-
puter’s power supply) to the power connector on
the SCSI device.

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Connecting External SCSI Devices
If you are connecting external SCSI devices to your
host adapter, you must obtain an external SCSI cable
for each external device you install.
1
Prepare each SCSI device for installation; config-
ure the SCSI ID and attach a terminating plug into
the last external device. For instructions, see the
device’s documentation as well as SCSI Configura-
tion Guidelines on page 2.
2
Plug the connector at one end of the external SCSI
cable into the host adapter’s external SCSI
connector.
3
Plug the connector at the other end of the cable to
either one of the SCSI connectors on the external
SCSI device.
4
To connect other external SCSI devices, daisy-
chain each device to the previous device until all
external SCSI devices have been connected.
Using the LED Connector
(Optional) Most computers have an LED disk activity
light on the front panel. If you disconnect the cable
from the LED connector on the motherboard and
connect it to the LED connector on the host adapter,
the LED on the front panel of the computer will light
whenever there is activity on the SCSI bus.
Reassembling the Computer
Be sure all power switches are OFF, then replace the
computer chassis cover and reconnect the power
cables to your computer and peripherals. Before
turning on your computer and peripherals, review
the following section, Configuring the Host Adapter. It
may be necessary to configure the host adapter.
Configuring the Host Adapter
The AHA-2940Ultra/2940Ultra Wide includes the
onboard, menu-driven SCSISelect configuration util-
ity, which allows you to change host adapter settings
without opening the computer or handling the
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board. SCSISelect also contains SCSI disk utilities
that let you low-level format or verify the disk media
of your SCSI hard disk drives.
SCSI
Select
Default Settings
The AHA-2940Ultra/2940Ultra Wide has the default
settings shown in the table on the following page.
The default settings are appropriate for most PCI
systems. If you do not need to change any of the
default settings, there is no need to run SCSISelect.
Your host adapter is ready for operation and you can
proceed to Installing Device Drivers on page 10.
For situations where you might want or need to
change the settings, see the descriptions of each set-
ting in the user’s guide. If you need to change any of
the default settings, or if you would like to format or
verify a disk, see Starting the SCSISelect Utility on
page 9 to start the utility.
SCSI Bus Interface Definitions Default
Host Adapter SCSI ID 7
SCSI Parity Checking Enabled
Host Adapter SCSI Termination Automatic
Boot Device Options Default
Boot SCSI ID 0
Boot LUN Number10
SCSI Device Configuration Default
Maximum Sync Transfer Rate 20.0 MBytes/sec2
40.0 MBytes/sec3
Enable Disconnection Yes (Enabled)
Initiate Wide Negotiation3Yes (Enabled)
Send Start Unit Command4Yes (Enabled)
Enable Write Back Cache N/C (No change)
BIOS Multiple LUN Support4No (Disabled)
Include in BIOS Scan Yes (Enabled)
Advanced Configuration Options Default
Plug and Play SCAM Support Disabled
Reset SCSI Bus at IC Initialization Enabled
Extended BIOS Translation for DOS Drives >
1 GByte Enabled
Verbose/Silent Mode Verbose
Host Adapter BIOS (Configuration Utility
reserves BIOS space) Enabled

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Starting the SCSI
Select
Utility
You can start the SCSISelect utility by pressing Ctrl-A
when the following prompt appears at boot time:
Press <Ctrl><A> for SCSISelect (TM) Utility!
The first menu that appears displays the options
Configure/View Host Adapter Settings and SCSI
Disk Utilities.
Using SCSI
Select
Menus
SCSISelect uses menus to list options you can select.
To select an option, use the ↑ and ↓ keys to move the
cursor to the option, then press Enter.
In some cases, selecting an option displays another
menu. You can return to the previous menu at any
time by pressing Esc. To restore the original SCSISelect
default values, press F6. To toggle the display
between color and monochrome modes, press F5 (this
feature may not work on some kinds of monitors).
Exiting SCSI
Select
To exit SCSISelect, press Esc until a message prompts
you to exit (if you changed any AHA-2940Ultra/
2940Ultra Wide settings, you are prompted to save
the changes before you exit). At the prompt, select
Yes to exit, then press any key to reboot the com-
puter. Any changes you made in SCSISelect take
effect after the computer boots.
Using the SCSI Disk Utilities
To access the SCSI disk utilities, select the SCSI Disk
Utilities option from the menu that appears after start-
ing SCSISelect. Once the option is selected, SCSISelect
Support Removable Disks Under BIOS as
Fixed Disks4Boot only
Display <Ctrl-A> Message During BIOS
Initialization4Enabled
BIOS Support for Bootable CD-ROMs4Enabled
BIOS Support for Int13 Extensions4Enabled
1 Setting is valid only if Multiple LUN Support is enabled
2 For AHA-2940
Ultra only
3 For AHA-2940
Ultra Wide only
4 Settings are valid only if host adapter BIOS is enabled

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immediately scans the SCSI bus and displays a list of
all SCSI IDs and the devices assigned to each ID.
When you select a specific ID and device, a small
menu appears, displaying the options Format Disk
and Verify Disk Media.
■Format Disk—This utility allows you to perform
a low-level format on a hard disk drive. Most
SCSI disk devices are preformatted at the factory
and do not need to be formatted again. The
Adaptec Format Disk utility is compatible with
the vast majority of SCSI disk drives.
■Verify Disk Media—This utility allows you to
scan the media of a hard disk drive for defects. If
the utility finds bad blocks on the media, it
prompts you to reassign them; if you select yes,
those blocks are no longer used. You can press Esc
at any time to abort the utility.
Installing Device Drivers
Some operating systems embed (include) the
AHA-2940Ultra/2940Ultra Wide device driver as part
of their installation software. These drivers work fine
with your AHA-2940Ultra/2940Ultra Wide; however,
the most recent version of the driver should be
installed in order for your AHA-2940Ultra/2940Ultra
Wide to perform at its optimum level.
If you purchased your AHA-2940Ultra/2940Ultra
Wide in a kit, the kit includes the latest Adaptec
EZ-SCSIand Adaptec 7800 Family Manager Set
software.
■Adaptec EZ-SCSI—allows you to install
software drivers for DOS, Windows®3.x, and
Windows®95/98 and includes several additional
utilities. Refer to the EZ-SCSI documentation for
more information.
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