******************************************************************************** OS2.TXT ******************************************************************************** Installation Guide for the Symbios SDMS OS/2 SYM8XX.ADD V4.09.00 and SYM_HI.ADD V4.10.00 drivers: Introduction Features Description Symbios Devices Supported Installing Your SDMS OS/2 Driver Driver Order in the CONFIG.SYS File Command Line Options Troubleshooting ******************************* Introduction ********************************* The OS/2 operating system version 4.0 provides an integrated platform featuring a graphical windowing interface, called Presentation Manager, that allows multiple applications to be viewed at the same time. Multitasking is also supported, enabling several different programs to run at the same time in different windows. Presentation Manager allows the user to switch between programs, start other programs, and maintain files and directories. This version of OS/2 requires an 80386 or higher microprocessor. Other hardware requirements include a minimum of 8 megabytes of RAM and a minimum hard disk drive size of 90 megabytes. Symbios SDMS 4.0 provides the necessary SCSI device drivers for OS/2: SYM8XX.ADD and SYM_HI.ADD. Symbios recommends reviewing the OS/2 manual prior to proceeding. * * * * * * * * * * * * * Features * * * * * * * * * * * o Supports synchronous negotiation (including Fast/Ultra SCSI/Ultra2 SCSI) o Supports Wide SCSI (single-ended and differential) o Supports multiple host adapters o Supports disconnect/reselect o Supports scatter/gather o Allows tagged command queuing o Supports single-ended, differential, and low-voltage differential termination o Allows target-initiated negotiation o Supports NVRAM/NVS configuration storage o Supports alternate CHS (Cylinder Head Sector) mapping algorithm New Features: o Allows up to 8 host adapters o Provides a command line /EXCLUDE option to block use of a specified adapter o Provides higher performance by requiring only one interrupt per I/O o Supports flexible GPIO pin definition using a table in the Manufacturing data area of Non-Volatile Memory * * * * * * * * * * * * Description * * * * * * * * * * * Although the Symbios SCSI controller's firmware can access the SCSI hard disk drives attached to the computer independently, the SCSI device drivers SYM8XX.ADD and SYM_HI.ADD act as an enhanced interface between the computer system and the SCSI BIOS firmware. Use of the device drivers increases the abilities of the SCSI controller firmware and fully utilizes the advancements and improvements of Pentium-based and higher microprocessors. The device drivers are also necessary to support the use of SCSI tape drives and CD-ROM drives with an OS/2 system. The Symbios SYM8XX.ADD and SYM_HI.ADD device drivers are written in compliance with the IBM OS/2 ADD (Adapter Device Driver) specification, and the device drivers work with third party applications that comply with the same specification. Both the SYM8XX.ADD V4.09.00 and SYM_HI.ADD V4.10.00 drivers allow up to 8 host adapters to be present in your system. The first 4 host adapters will be accessed in the order you specify using the SCSI BIOS Configuration Utility provided with some members of the 8XX family of host adapters. Refer to your host adapter's user guide for information on the availability and use of the SCSI BIOS Configuration Utility. Remaining host adapters will be accessed based on their physical position in your system. Refer to your system documentation for further information. * * * * * * * * * * Symbios Devices Supported * * * * * * * * The SYM8XX.ADD driver supports the following devices and associated Symbios host adapters: SYM53C810, SYM53C810A, SYM53C810AE (SYM8100S, SYM8100ASP) SYM53C815 (SYM815XS, SYM8150SP) SYM53C825, 53C825A (SYM8250S, SYM8251S, SYM8251D, SYM8250ASP, SYM8251ASP,SYM8251AD) SYM53C860, SYM53C860AE (SYM8600SP) SYM53C875, SYM53C875E (SYM8750SP, SYM8751SP, SYM8751D) SYM53C876 (SYM22801, SYM22802) SYM53C885 SYM53C895 (SYM8951U) The SYM_HI.ADD driver supports the following device and associated Symbios host adapter: SYM53C896 (SYM22910) ************************* Installing Your SDMS OS/2 Driver ******************** Installing SYM8XX.ADD/SYM_HI.ADD with OS/2 Already Installed Installing SYM8XX.ADD/SYM_HI.ADD and OS/2 from a Floppy to a SCSI Hard Drive Installing SYM8XX.ADD/SYM_HI.ADD and OS/2 from a SCSI CD-ROM to a SCSI Hard Drive These installation instructions are specific and accurate for the SDMS OS/2 V4.09.00 driver: SYM8XX.ADD and V4.10.00 driver: SYM_HI.ADD. Refer to the text file OS2.TXT located on the SDMS diskette for a version of these instructions guaranteed to match your driver. The Symbios device driver floppy diskette contains six files for OS/2: 1. Device drivers SYM8XX.ADD and SYM_HI.ADD, 2. Text files SYM8XX.DDP and SYM_HI.DDP, and 3. Executable files SYM8XXPC.EXE and SYM_HIPC.EXE. When the device driver installation utility under OS/2 is activated, it looks for all files with the DDP extension. The DDP file contains the necessary information to install the SCSI device driver. The EXE file contains a utility that verifies that an appropriate adapter is present. If you do not wish to install both device drivers, create a floppy diskette containing the appropriate driver, DDP file and EXE file to use instead of the Symbios device driver floppy diskette. Note: If you previously installed OS2CAM.ADD (a previous version of the SYM8XX.ADD driver), delete OS2CAM.ADD and the corresponding BASEDEV= statement in the CONFIG.SYS file after you complete the installation procedures. If you previously installed SYM8XX.ADD and/or SYM_HI.ADD in a directory other than \OS2\BOOT, move SYM8XX.ADD and/or SYM_HI.ADD to \OS2\BOOT, where the new versions of these drivers can replace the old versions. The system will continue to boot using the previous drivers until these steps are taken. * * * Installing SYM8XX.ADD/SYM_HI.ADD with OS/2 Already Installed * * * At the OS/2 Desktop, open the System Setup folder located within the OS/2 System ' folder and follow these steps: 1. Open the Install/Remove folder and then double-click on the Device Driver Install icon. 2. Insert the floppy diskette containing the Symbios device driver(s) in the source drive. The system will find all DDP files on the floppy diskette and automatically install the corresponding drivers. 3. To make sure that the installation was successful, open the Utilities folder located within the Programs folder on the OS/2 Desktop. Then double-click on the OS/2 System Editor to start the editor. Open the CONFIG.SYS file in the root directory and find the line(s): BASEDEV=SYM8XX.ADD /V and/or BASEDEV=SYM_HI.ADD /V Then check that the appropriate drivers are in the \OS2\BOOT directory on the boot drive. * Installing SYM8XX.ADD/SYM_HI.ADD and OS/2 from a Floppy to a SCSI Hard Drive * In this case, since OS/2 will be installed from a floppy diskette, it is not required that the driver be present to install the operating system (as is the case when installing from a CD-ROM). The following steps allow installation of OS/2 from a floppy diskette: 1. After the installation of OS/2 completes and the WorkPlace Shell desktop builds, open the System Setup folder located in the OS/2 System folder. Open the Install/Remove folder and then double-click on the Device Driver Install icon. 2. Insert the floppy diskette containing the Symbios device driver(s) in the source drive. The system will find all DDP files on the floppy diskette and automatically install the corresponding drivers. 3. To make sure that the installation was successful, open the Utilities folder located within the Programs folder on the OS/2 Desktop. Then double-click on the OS/2 System Editor to start the editor. Open the CONFIG.SYS file in the root directory and find the line(s): BASEDEV=SYM8XX.ADD /V and/or BASEDEV=SYM_HI.ADD /V Then check that the appropriate drivers are in the \OS2\BOOT directory on the boot drive. 4. Continue with the OS/2 installation process as documented in the OS/2 Installation Guide. * Installing SYM8XX.ADD/SYM_HI.ADD and OS/2 from a SCSI CD-ROM to a SCSI Hard Drive * To install OS/2 from a SCSI CD-ROM attached to a Symbios host adapter, the SCSI driver must be present in order to access the CD-ROM. The following steps allow installation of OS/2 from a SCSI CD-ROM: 1. Make copies of the floppy diskettes used for installation that are included with the CD-ROM version of OS/2. 2. Determine the appropriate driver for installation by locating the host adapter to which the CD-ROM is attached in the section of this guide titled "Symbios Devices Supported". Then copy the indicated driver to the copy of Diskette 1. In order to do so, you must delete files on Diskette 1 to provide space. Consult the README.1ST file on the Device Driver Pak Volume 1.0 CD. It contains a list of files that may not be deleted. Follow the instructions provided in the README.1ST file. Once space is made available on Diskette 1, copy the appropriate Symbios device driver onto this diskette. When .ADD drivers are deleted from Diskette 1, make certain to delete or remark out the corresponding BASEDEV= statement in the CONFIG.SYS file. Otherwise, error messages will show up during installation. 3. Edit the CONFIG.SYS file on the copy of Diskette 1 by adding one of the following lines at the end of the file: BASEDEV=SYM8XX.ADD /V or BASEDEV=SYM_HI.ADD /V Follow the directions in the README.1ST file for adding the following line to the CONFIG.SYS file: SET COPYFROMFLOPPY=1 This allows the Symbios driver to be copied from the installation diskette to the system's boot drive. 4. Place the copy of Installation Diskette in the A: drive and reboot the computer. 5. Proceed with the OS/2 installation process as documented in the OS/2 Installation Guide. * * * * * * * * Driver Order in the CONFIG.SYS File * * * * * * * Because of the way OS/2 assigns drive letters, the order in which drivers appear in the CONFIG.SYS file is important. The drivers must appear in the order in which the drive letters are to be assigned. In particular: 1. OS/2 Warp will install the BASEDEV= line at the beginning of the target system's CONFIG.SYS file regardless of where the line is located in that file on Diskette 1. You may need to rearrange the order in which drivers appear in the CONFIG.SYS file for the target system. 2. The driver for the host adapter to which the boot device is attached must appear before all other BASEDEV=drivers in the CONFIG.SYS file. 3. If you are installing both Symbios drivers, the driver corresponding to the host adapter with the boot drive attached must appear first in the CONFIG.SYS file. Refer to the OS/2 documentation to fully understand this requirement. * * * * * * * * * * * Command Line Options * * * * * * * * * Using the /VERBOSE Option Using the /!DM Option Using the /!SM Option Using the /EXCLUDE Option Using the /SYNCH_RATE Option Using the /SYNCH_OFFSET Option Using the /TIMEOUT Option Using the /DISCONNECT Option Using the /PARITY Option Using the /QTAG Option Using the /WIDTH Option The host adapter has a default configuration that consists of optimal values for operation. You may decide to alter these default values if there is a conflict between device settings or if you need to optimize system performance. Some values may be changed using the SCSI BIOS Configuration Utility provided with some members of the 8XX family of host adapters. Refer to the host adapter's user guide for information on the availability and use of the SCSI BIOS Configuration Utility. In addition, the Symbios OS/2 device drivers have several embedded functions that can be accessed via switches on the command line in the CONFIG.SYS file. Note: Values are applied in the following order: o Manufacturer's settings o SCSI BIOS Configuration Utility changes o Command line options At any point during this process, subsequent changes in synchronous and wide negotiations may only decrease speed or reduce width. Any changes that attempt to increase speed or width will be ignored. The options available using command line switches are described below. The SYM8XX.ADD driver is used in all examples; SYM_HI.ADD may be substituted for SYM8XX.ADD with identical results. * * * Using the /VERBOSE (or /V) Option * * * This option appears on the command line by default. It enables display of a banner, version number, and SCSI bus information during start up of the system. Usage: /VERBOSE For example, if you wish to see more detailed information displayed when booting, the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /VERBOSE or BASEDEV=SYM8XX.ADD /V To disable this feature, remove this switch from the command line. * * * Using the /!DM Option * * * This option disables use of the IBM-supplied DASD manager (OS2DASD.DMD) for the devices listed. The DASD manager supports direct access devices such as hard drives. Usage: /!DM[,]* Where: hba represents the logical number of a host adapter as displayed by the Verbose option in the column headed "HBA". This is not the SCSI ID of the host adapter. Use an hba value with no :id following it to indicate all devices on an adapter. id represents a SCSI target ID on the indicated adapter. To indicate all devices on a host adapter, do not use the SCSI ID of the host adapter for the id value. Instead, use the hba value as indicated in the preceding paragraph. [ ] indicate optional information. * indicates the pattern enclosed in the [ ] may be repeated. For example, to disable OS2DASD.DMD for devices on host adapter 0 at target IDs 3 and 5, the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /!DM<0:3>,<0:5> * * * Using the /!SM Option * * * This option disables use of the IBM-supplied SCSI manager (OS2SCSI.DMD) for the devices listed. The SCSI manager supports SCSI tape drives. Usage: /!SM[,]* Where: hba represents the logical number of a host adapter as displayed by the Verbose option in the column headed "HBA". This is not the SCSI ID of the host adapter. Use an hba value with no :id following it to indicate all devices on an adapter. id represents a SCSI target ID on the indicated adapter. To indicate all devices on a host adapter, do not use the SCSI ID of the host adapter for the id value. Instead, use the hba value as indicated in the preceding paragraph. [ ] indicate optional information. * indicates the pattern enclosed in the [ ] may be repeated. For example, if you want to disable OS2SCSI.DMD for devices on host adapter 0 at target IDs 3 and 5, the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /!SM<0:3>,<0:5> * * * Using the /EXCLUDE (or /X) Option * * * This option disables a host adapter so that it is not seen by the Symbios OS/2 device drivers. This allows a host adapter to be ignored without physically removing the board from the system. This may be necessary if the adapter in question is causing a resource conflict. Usage: /EXCLUDE[,]* Where: chip is a unique identifier that indicates the Symbios board type. The Verbose option displays a table with this value appearing in the "CHIP" column. bus represents the PCI bus number into which the adapter is plugged. The Verbose option displays a table with this value appearing in the "BUS" column. dev/func is the number derived by combining the PCI device and function numbers and functions as a unique board identifier in conjunction with the PCI bus. The Verbose option displays a table with this hexadecimal value appearing in the "DEV/FUNC" column. It may contain an A, B, C, D, E, or F as part of its value. [ ] indicate optional information. * indicates the pattern enclosed in the [ ] may be repeated. For example, to exclude a host adapter with chip type F, PCI bus number 0 and dev/func number A0, the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /EXCLUDE Note: If you exclude the adapter to which the boot device is attached, then you will not be able to boot. * * * Using the /SYNCH_RATE (or /SR) Option * * * This option sets the maximum synchronous transfer rate (in megabyte transfers per second) to negotiate with a particular device. The allowable values for this setting are 0, 5, 10, 20, and 40 megabyte transfers per second, if the adapter is capable of the specified speed. All host adapters in the 8XX family support at least 10 megabyte transfers per second; some support 20 or 40 megabyte transfers per second. To turn off synchronous transfers for a particular device, specify 0 (zero). The value set by this option only defines the maximum transfer rate negotiated. The actual rate also depends on what the device can do. The default value is the fastest transfer rate that is supported by a particular host adapter. Usage: /SYNCH_RATE=n[,n]* Where: n = 0, 5, 10, 20 or 40. hba represents the logical number of a host adapter as displayed by the Verbose option in the column headed "HBA". This is not the SCSI ID of the host adapter. Use an hba value with no :id following it to indicate all devices on an adapter. id represents a SCSI target ID on the indicated adapter. To indicate all devices on a host adapter, do not use the SCSI ID of the host adapter for the id value. Instead, use the hba value as indicated in the preceding paragraph. [ ] indicate optional information. * indicates the pattern enclosed in the [ ] may be repeated. For example, to turn off synchronous transfers to ID 3 on host adapter 0, the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /SYNCH_RATE=0<0:3> As another example, to set synchronous transfers to 10 megabyte transfers per second on all devices on adapter 1, the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /SR=10<1> Note: The maximum synchronous transfer rates effectively double when the adapter and device permit wide transfers (See the /WIDTH option). For example, a synchronous transfer rate setting of 40 megabyte transfers per second will actually produce a transfer rate of 80 megabyte transfers per second if the adapter and device both allow and are set to perform wide transfers. * * * Using the /SYNCH_OFFSET (or /SO) Option * * * This option sets the maximum synchronous offset to negotiate with a particular device. The allowable values for this setting are 0 to the maximum synchronous offset supported by the specified adapter. The SYM53C8XX controller chips support offsets up to 31. Refer to your host adapter's user guide for information on the maximum offset supported by your host adapter. If 0 (zero) is specified for the synchronous offset value, synchronous transfers are turned off for any specified device. The value set by this option only defines the maximum offset that is negotiated. The resulting rate also depends on the device capability. The default value is the maximum offset that is supported by a particular host adapter. Usage: /SYNCH_OFFSET=n[,n]* Where: n = 0..maximum synchronous offset for the adapter. hba represents the logical number of a host adapter as displayed by the Verbose option in the column headed "HBA". This is not the SCSI ID of the host adapter. Use an hba value with no :id following it to indicate all devices on an adapter. id represents a SCSI target ID on the indicated adapter. To indicate all devices on a host adapter, do not use the SCSI ID of the host adapter for the id value. Instead, use the hba value as indicated in the preceding paragraph. [ ] indicate optional information. * indicates the pattern enclosed in the [ ] may be repeated. For example, to change the synchronous offset to 6 for ID 3 on host adapter 0, the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /SYNCH_OFFSET=6<0:3> * * * Using the /TIMEOUT (or /T) Option * * * The Symbios device drivers use a time-out mechanism to detect certain errors. When the driver issues a command to a SCSI device, a timer is started. If the timer expires before the command completes, the driver assumes that something has gone wrong with the device, and takes steps to recover. The default value for this is 10 seconds. If you set the value to be less than the system has allocated for a particular device, your value will be ignored. To turn off the time-out mechanism for a particular device, set the value to 0 (zero). Usage: /TIMEOUT=n[,n]* Where: n = time-out value in seconds for device, n=(0..65535) hba represents the logical number of a host adapter as displayed by the Verbose option in the column headed "HBA". This is not the SCSI ID of the host adapter. Use an hba value with no :id following it to indicate all devices on an adapter. id represents a SCSI target ID on the indicated adapter. To indicate all devices on a host adapter, do not use the SCSI ID of the host adapter for the id value. Instead, use the hba value as indicated in the preceding paragraph. [ ] indicate optional information. * indicates the pattern enclosed in the [ ] may be repeated. For example, if you have a particularly slow device on ID 3 on host adapter 0 and you wish to extend the time out on this device to 60 seconds, then the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /TIMEOUT=60<0:3> * * * Using the /DISCONNECT (or /DC) Option * * * SCSI devices have the ability to disconnect from the bus during an I/O transfer. This option allows (or does not allow) a device to disconnect during an I/O transfer. If a particular adapter has parity checking disabled, then you must use this option to disable disconnects for all devices on that adapter that do not generate parity. Refer to the /PARITY option for more information. Usage: /DISCONNECT=n[,n]* Where: n = ON or OFF. hba represents the logical number of a host adapter as displayed by the Verbose option in the column headed "HBA". This is not the SCSI ID of the host adapter. Use an hba value with no :id following it to indicate all devices on an adapter. id represents a SCSI target ID on the indicated adapter. To indicate all devices on a host adapter, do not use the SCSI ID of the host adapter for the ID value. Instead, use the hba value as indicated in the preceding paragraph. [ ] indicate optional information. * indicates the pattern enclosed in the [ ] may be repeated. Valid options are "ON" (allow disconnects) and "OFF" (do not allow disconnects). The default for all devices is "ON". For example, if you want to disable disconnects on the device at ID 2 on host adapter 0, then the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /DISCONNECT=OFF<0:2> * * * Using the /PARITY (or /P) Option * * * The SYM53C8XX chips are capable of enabling or disabling the SCSI bus data integrity checking feature known as "parity". Some non-SCSI compliant devices sold as SCSI devices do not generate parity. You can use this option to disable parity checking. The SYM53C8XX chips always generate parity (for outputs), but may optionally check the parity (for inputs). Usage: /PARITY=n[,n]* Where: n = ON or OFF. hba represents the logical number of a host adapter as displayed by the Verbose option in the column headed "HBA". This is not the SCSI ID of the host adapter. [ ] indicate optional information. * indicates the pattern enclosed in the [ ] may be repeated. Valid options are "ON" (check parity) and "OFF" (do not check parity). The default for all devices is "ON", which enables parity checking for all devices. For example, to turn off parity checking on host adapter number 0, the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /PARITY=OFF<0> Note: When disabling parity checking, it is necessary to disable disconnects for any device that does not generate parity, as the SYM53C8XX chips cannot disable parity checking for that device during the reselection phase. If a device does not generate parity and it disconnects, the I/O never completes as the reselection never completes. Refer to using the /DISCONNECT option for more information about disabling disconnects for a device. * * * Using the /QTAG (or /QT) Option * * * Queue tagging allows more than one outstanding command per SCSI device. Some non-SCSI compliant devices sold as SCSI devices do not allow queue tags, in which case queue tagging needs to be disabled. The value given in the command line will be the depth of the queue for queue tags for the device(s) indicated. To disable queue tag support, a value of 0 or 1 should be given. Usage: /QTAG=n[,n]* Where: n = the number of queue tags allowed for a device (0..256). hba represents the logical number of a host adapter as displayed by the Verbose option in the column headed "HBA". This is not the SCSI ID of the host adapter. Use an hba value with no :id following it to indicate all devices on an adapter. id represents a SCSI target ID on the indicated adapter. To indicate all devices on a host adapter, do not use the SCSI ID of the host adapter for the id value. Instead, use the hba value as indicated in the preceding paragraph. [ ] indicate optional information. * indicates the pattern enclosed in the [ ] may be repeated. For example, to turn off queue tagging for ID 3 on host adapter number 0, the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /QTAG=0<0:3> As another example, to set the queue depth to 5 for all devices on host adapter number 2, the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /QT=5<2> * * * Using the /WIDTH (or /W) Option * * * Devices attached to a SCSI bus are narrow or wide devices. Narrow devices transfer data one byte (or 8 bits) at a time. Wide devices transfer two bytes (or 16 bits) at a time. The value given in the command line option will determine the size of data transfers. Usage: /WIDTH=n[,n]* Where: n = 8 or 16. hba represents the logical number of a host adapter as displayed by the Verbose option in the column headed "HBA". This is not the SCSI ID of the host adapter. Use an hba value with no :id following it to indicate all devices on an adapter. id represents a SCSI target ID on the indicated adapter. To indicate all devices on a host adapter, do not use the SCSI ID of the host adapter for the id value. Instead, use the hba value as indicated in the preceding paragraph. [ ] indicate optional information. * indicates the pattern enclosed in the [ ] may be repeated. For example, to have the device at ID 3 on host adapter number 0 treated as a narrow device, the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /WIDTH=8<0:3> As another example, to have all devices on host adapter number 2 treated as 8-bit devices, the line in the CONFIG.SYS file that loads SYM8XX.ADD should look like this: BASEDEV=SYM8XX.ADD /W=8<2> * * * * * * * * * * * Troubleshooting * * * * * * * * * * * The following are some potential problems and their suggested solutions: 1. Problem: You cannot access the SCSI device(s). Solution: a. Make sure the SCSI device driver is installed properly. b. Make sure each device has power. c. Verify that the appropriate BASEDEV= line (BASEDEV=SYM8XX.ADD /V or BASEDEV=SYM_HI.ADD /V) exists in the CONFIG.SYS file. d. Check the ordering of BASEDEV= entries in the CONFIG.SYS file to be sure that the boot device is loaded first. e. Verify that the correct driver is in the appropriate directory (\OS2\BOOT). f. Check the cable connections and the host adapter installation. g. Verify that the adapter is not turned off in the SCSI BIOS Configuration Utility and that the adapter is not excluded using the /EXCLUDE command line option. 2. Problem: The computer hangs or locks up when booting and the SCSI devices attached are not seen by the computer system. Solution: a. Make sure that all the SCSI devices are configured at different ID numbers. If booting the system from a device on the SCSI bus, the boot drive must have the lowest ID or the highest ID. This depends on the scan order option selected in the SCSI BIOS Configuration Utility. For more information, consult the BOOTROM.TXT file or the documentation provided with the host adapter board. b. Make sure both, but only, the ends of the SCSI bus are terminated. c. Make sure the device driver is listed in the CONFIG.SYS file (and loaded when booting). 3. Problem: The device driver does not see one of the SCSI devices. Solution: a. Reboot the computer. b. Make sure the SCSI devices have different ID numbers. c. Make sure both, but only, the ends of the SCSI bus are terminated. d. Check the cable and power connections. e. Check the ordering of BASEDEV= entries in the CONFIG.SYS file to be sure that the boot device is loaded first. f. Verify that the adapter is not turned off in the SCSI BIOS Configuration Utility and that the adapter is not excluded using the /EXCLUDE command line option. 4. Problem: OS/2 attempts to install to or boot from an IDE drive instead of the SCSI drive. Solution: The system BIOS finds the IDE drive before it finds the SCSI drive, and therefore uses the IDE drive as the boot device. a. Check that the appropriate BASEDEV= line (BASEDEV=SYM8XX.ADD /V or BASEDEV=SYM_HI.ADD /V) appears first in the CONFIG.SYS file. b. Disable the IDE drive in the CMOS setup. c. On some hardware platforms, the IDE drive must be physically disconnected before installing to a SCSI drive. 5. Problem: The following message appears at bootup: "OS/2 is unable to operate your hard disk or diskette drive. The system is stopped. Correct the preceding error and restart the system." Solution: a. This problem occurs when the system is booting from a hard drive attached to an IDE bus, a SCSI disk is attached to the Symbios host adapter, and the Symbios BASEDEV= line (BASEDEV=SYM8XX.ADD /V or BASEDEV=SYM_HI.ADD /V) appears in the CONFIG.SYS file before the IDE device driver statement. -OR- This problem occurs when the system is booting from a hard drive attached to the Symbios adapter, an IDE drive is in the system, and the IDE BASEDEV= line appears in the CONFIG.SYS file before the Symbios BASEDEV= line (BASEDEV=SYM8XX.ADD /V or BASEDEV=SYM_HI.ADD /V). b. Boot the system using the floppy drive and installation diskettes to the F3=Command Prompt screen. Use the TEDIT.EXE editor to edit the CONFIG.SYS file. Move the BASEDEV= statements to be in the appropriate order for the system's configuration. c. Restart your system.