ICP Chapter C User manual

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In the previous chapter we installed the ICP Controller in a PCI computer and connected the
SCSI devices. Now these SCSI devices must be prepared in order to run with your operating
system. This Quick-Setup chapter should help you to get started quickly. Quick-Setup
shows four examples on how a single SCSI hard disk, a Mirroring Array Drive (RAID 1), a
RAID 5 Array Drive and a RAID 5 Array Drive with a Hot Fix drive are installed:
Example 1: Installing a single SCSI hard disk.
Example 2: Installing a Mirroring Array Drive (RAID 1), consisting of two
SCSI hard disks.
Example 3: Installing a RAID 5 Array Drive, consisting of five identical
SCSI hard disks.
Example 4: Installing a RAID 5 Array Drive, consisting of four identical
SCSI hard disks, and adding one Hot Fix SCSI hard disk.
Examples 3 and 4 are not applicable to ICP Controllers without the RAIDYNE firmware.
Even if you cannot practically carry out all the examples yourself, we suggest reading them
all the same because they will give you a better understanding of how the controllers of the
GDT RP Series work. The following table tells you which examples are applicable to your
type of ICP Controller.
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<HV, when RAIDYNE Upgrade installed.
With examples 3 and 4 we shall briefly repeat the installation of the ICP Controller and the
SCSI devices, in particular with regard to disk arrays.
Some essential issues having direct impact on the structure and configuration of an Array
Drive with RAIDYNE will also be discussed:

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1. How many physical SCSI hard disks are to be integrated in the Array Drive ?
2. Which redundancy level ought to be achieved ?
3. Should RAIDYNE automatically recover redundancy in the event of a disk
failure ? Or, in other terms: Are Hot Fix drives needed ?
Before we go through these examples step by step, we would like to explain a few terms and
relations important for the basic understanding of the ICP Controller firmware. At the end of
example 4, we will try to answer the three questions above.
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We refer to firmware as the operating system which controls the ICP Controller with all its
functions and capabilities. The firmware exclusively runs on the ICP Controller and is stored
in the Flash-RAM on the ICP Controller PCB. The controlling function is entirely independ-
ent of the PCI computer and the host operating system installed (for example UNIX), and
does not "drain" any computing power or time from the PCI computer. According to the
performance requirements needed, the ICP Controllers are available with two firmware vari-
ants. The firmware is either already installed on the controller upon delivery, or can be
added as an upgrade: RAIDYNE upgrade.
Standard Firmware (installed on the GDT61xyRP controllers).
In addition to simple controlling functions regarding SCSI hard disks or removable
hard disks, this version allows disk chaining (several drives can be linked in order to
form a single "large" drive), and the configuration of Array Drives of the types data
striping (RAID 0) and disk mirroring or duplexing (RAID 1).
RAIDYNE Firmware (installed on the GDT65xyRP controllers). In addition to disk
chaining, RAID 0 and RAID 1, RAIDYNE allows you to install and control Array
Drives of the types RAID 4 (data striping with dedicated parity drive), RAID 5 (data
striping with distributed parity) and RAID10 (a combination between RAID 0 and 1)
RAIDYNE is the name of the ICP disk-array operating system for the ICP Controllers. Unlike
pure software solutions, RAIDYNE is totally independent of the host operating system, and
can therefore be accessed under MS-DOS, Windows, OS/2, SCO-UNIX, Interactive UNIX,
Novell NetWare, etc.. Special RAID drivers are not needed. The integration of a RAID Disk
Array into the host operating system is carried out with the same drivers used for the inte-
gration of a single SCSI hard disk. All ICP Controllers are equipped with a hardware which is
particularly well suited for disk arrays. RAIDYNE uses this hardware with extreme efficiency
and therefore allows you to configure disk arrays that do not load the host computer
(whereas all software-based RAID solutions more or less reduce the overall performance of
the host computer.).
The basic concept of the RAIDYNE is strictly modular, and consequently, in
its functioning it appears to the user as a unit construction system.

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According to the adjusted stripe size (e.g., 16 KB) and the number of hard disks, the data
blocks are split into
stripes. Each stripe is
stored on a separate
hard disk. Especially
with sequential read
and write operations,
we can observe a sig-
nificant improvement
of the data through-
put. RAID 0 includes
no redundancy at all,
i.e., when one hard
disk fails, all data is
lost.
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two identical hard disks.
When one hard disk fails,
all data are immediately
available on the other
without any impact on
the performance and data
integrity.
We talk about "Disk Mir-
roring" when two hard
disks are mirrored on one
SCSI channel. If each
hard disk is connected
with a separate SCSI
channel, this is called
"Disk Duplexing"
(additional security).
RAID 1 represents an easy
and highly efficient solu-
tion for data security and
system availability. It is
especially suitable for
installations which are
not too large (the capacity
available is only half of
the installed capacity).

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RAID 4 works in the same way as RAID 0. The data are striped amongst the hard disks. Addi-
tionally, the controller
calculates redundancy
data (parity information)
which are stored on a
separate hard disk (P1,
P2, ...). Even when one
hard disk fails, all data
are still fully available.
The missing data is re-
calculated from the data
still available and the
parity information. Un-
like in RAID 1, only the
capacity of one hard disk
is needed for the redundancy. If we consider, for example, a RAID 4 disk array with 5 hard
disks, 80% of the installed hard disk capacity is available as user capacity, only 20% is used
for redundancy. In situations with many small data blocks, the parity hard disk becomes a
throughput bottle-neck. With large data blocks, RAID 4 shows significantly improved per-
formance.
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Unlike RAID 4, the parity data in a RAID 5 disk array are striped in all hard disks. The RAID 5
disk array delivers a balanced throughput. Even with small data blocks, which are very likely
in a multi-tasking and
multi-user environ-
ment, the response
time is very good. RAID
5 offers the same level
of security as RAID 4.
When one hard disk
fails, all data are still
fully available, the
missing data are recal-
culated from the data
still available and the
parity information.
RAID 4 and RAID 5 are
particularly suitable for
systems with medium to large capacity requirements, due to their efficient ratio of the in-
stalled and actually available capacity.

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The idea behind RAID
10 is simply based on
the combination of
RAID 0 (Performance)
and RAID 1 (Data Secu-
rity). Unlike RAID 4 and
RAID 5, there is no
need to calculate parity
information. RAID 10
disk arrays offer good
performance and data
security. As in RAID 0,
optimum performance
is achieved in highly
sequential load situa-
tions. Identical to RAID
1, 50% of the installed
capacity is lost for re-
dundancy.
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Any installation or maintenance procedures regarding the ICP Controller are carried out
with the configuration program GDTSETUP. The monitoring program GDTMON allows a
continuous monitoring and maintenance of the ICP Controller and the connected disk ar-
rays. The GDTMON utility also includes options to replace a defective drive with a new one
(Hot Plug) and is available for most of the operating systems supported by the ICP Con-
trollers. GDTSETUP allows you to set up single disks or complex disk arrays with simple and
user-friendly installation procedures. Little previous knowledge is needed to be able to use
GDTSETUP efficiently. It is only necessary to understand the hierarchy levels in the ICP Con-
troller firmware (which are the same for both firmware versions: Standard and RAIDYNE).
For the user's convenience the GDTSETUP program is available in two different variants:
GDTSETUP loaded from the ICP Controller's Flash-RAM after switching on the computer
GDTSETUP loaded from disk under MS-DOS.
The header of the GDTSETUP program indicates with a letter after the version number
whether GDTSETUP was loaded from disk or from Flash-RAM:
"R" for GDTSETUP loaded from the Flash-RAM after switching on the computer
"D" for GDTSETUP loaded from Disk, i.e., under MS-DOS.
Loading GDTSETUP with <CTRL><G> from the Flash-RAM is very comfortable since no op-
erating system is required to carry out the configuration and setup works.
On the other side, loading GDTSETUP from disk (i.e., under MS-DOS) becomes necessary
for tasks like partitioning or enabling a totally disabled GDT BIOS (which includes
GDTSETUP).

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Whenever you load GDTSETUP and select the desired ICP Controller, it comes up in its
EXPRESS Setup mode. This mode does not require any previous knowledge. If you choose
this function, GDTSETUP carries out the complete installation entirely on its own, providing
you for example with a fully operational RAID 5 Array Drive with optimized settings (for in-
stance, with all SCSI features of a given drive activated).
After selecting Configure Host Drives, select Create new Host Drive.

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GDTSETUP scans the system for "free" hard disks (i.e., drives which are not yet part of other
Host Drives). Use the <SPACE>-bar to select the desired hard disks (they are marked with
an "*"). On the right side GDTSETUP offers highlighted the possible configurations with
these drives.
Pressing <ENTER> ends the selection.

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After choosing a configuration type for an Array Drive, GDTSETUP displays a security re-
quest.
After the confirmation, the Host Drive is automatically built up and configured.
After leaving GDTSETUP the parity information is generated.

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For chapter C, we do not use this function, but give detailed instructions on how to set up a
single disk and disk arrays with GDTSETUP and its Enhanced Setup.
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Both GDT firmware versions (Standard and RAIDYNE) are based on four fundamental levels
of hierarchy. Each level has its "own drives" ( = components). The basic rule is:
To build up a “drive“ on a given level of hierarchy, the “drives“ of the next lower level
of hierarchy are used as components.
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Physical Drives = hard disks, removable hard disks, some MO drives (1) are located on the
lowest level. They are the basic components of all "drive constructions" you can set up.
However, before they can be used by the firmware, these hard disks must be "prepared", a
procedure we call initialization. During this initialization each hard disk receives information
which allows a univocal identification even if the SCSI-ID or the controller is changed. For
reasons of data coherency, this information is extremely important for any drive construc-
tion consisting of more than one physical drive.
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On the next higher level are the Logical Drives. Logical Drives are introduced to obtain full
independence of the physical coordinates of a physical device. This is necessary to easily
change the whole ICP Controller and the channels, IDs, without loosing the data and the
information on a specific disk array.
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On this level of hierarchy, the firmware forms the Array Drives. Depending on the firmware
installed, this can be
Single Disks (one hard disk, some vendors call it JBOD - Just A Bunch Of Drives)
Chaining Sets (concatenation of several hard disks)
RAID 0 Array Drives
RAID 1 Array Drives, RAID 1 Array Drives plus hot fix drive
RAID 4 Array Drives, RAID 4 Array Drives plus hot fix drive
RAID 5 Array Drives, RAID 5 Array Drives plus hot fix drive
RAID 10 Array Drives, RAID 10 Array Drives plus hot fix drive
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On the highest level of hierarchy, the firmware forms the Host Drives. In the end, only these
Host Drives can be accessed by the host operating system of the computer. Drives C, D, etc.
under MS-DOS, OS/2, etc. are always referred to as Host Drives by the firmware. The same
applies to NetWare- and UNIX-drives. The firmware automatically transforms each newly
installed Logical Drive and Array Drive into a Host Drive. This Host Drive is then assigned a
Host Drive number which is identical to its Logical Drive or Array Drive number.
The firmware is capable of running several Host Drives of the most various kinds at the
same time. An example for MS-DOS: drive C is a RAID 5 type Host Drive (consisting of 5
SCSI hard disks), drive D is a single hard disk, and drive E is a CD-ROM communicating with
RAIDYNE through corelSCSI and the GDT ASPI manager.
On this level the user may split an existing Array Drive into several Host Drives.
(1) Also see section C.5.

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After a capacity expansion of a given Array Drive the added capacity appears as a new Host
Drive on this level. It can be either used as a separate Host Drive, or merged with the first
Host Drive of the Array Drive.
Within GDTSETUP, each level of hierarchy has its own special menu:
/HYHO ÖMenu: Configure Physical Devices
/HYHO ÖMenu: Configure Logical Drives
/HYHO ÖMenu: Configure Array Drives
/HYHO ÖMenu: Configure Host Drives
Generally, each installation procedure passes through these 4 menus, starting with level 1.
Therefore:
First initialize the Physical Drives.
Then configure the Logical Drives.
Then configure the Array Drives (e.g. Array Drives with RAID 0, 1, 4, 5
and 10).
Finally, configure the Host Drives.
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A SCSI device that is not a SCSI hard disk or a removable hard disk, or that does not behave
like one, is called a Not Direct Access Device.
Such a device is not configured with GDTSETUP and does not form a Logical or Host
Drive. SCSI devices of this kind are either operated through the ASPI interface (Advanced
SCSI programming Interface) (MS-DOS, Windows, Novell NetWare or OS/2), or are directly
accessed from the operating system (UNIX, Windows NT). For more information on how to
use these devices, please refer to the corresponding chapters of this manual. Note: hard
disks and removable hard disks are called Direct Access Devices. However, there are some Not
Direct Access Devices, for instance certain MO drives, which can be operated just like remov-
able hard disks if they have been appropriately configured before (for example by changing
their jumper setting).
But enough on the dry theory. Now here are the examples which explain step by step
all the necessary basics for setting up Host Drives with your ICP Controller
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This example is applicable to all ICP Controllers.
We presume that the controller and the SCSI hard disks have been installed properly.
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You can load GDTSETUP in two ways:
1.Press the <CTRL><G> key combination when the GDT BIOS message comes up (shortly
after switching on the computer) and load GDTSETUP from the Flash-RAM of the ICP
Controller. In this case no operating system is required.

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If GDTSETUP was loaded this way, there is an "R" (ROM) behind the version number.
2.Load GDTSETUP from disk under MS-DOS. Boot the MS-DOS-operating system (either
from a boot-floppy or from an already existing boot drive, i.e., IDE-hard disk etc.). In or-
der for GDTSETUP to work properly, you have to load the device driver GDTX000 first.
This can be done in two ways:
a.) Load GDTX000 from the DOS-command level by typing in GDTX000<ENTER>
b.) Load GDTX000 automatically through the CONFIG.SYS file (DEVICE=GDTX000.EXE)
Note: GDTSETUP.EXE as well as GDTX000.EXE are on the System Disk - DOS.
If GDTSETUP was loaded this way, there is a "D" (Disk) behind the version number.
You may now ask what are the differences between the two GDTSETUP variants ?
They are small. The GDTSETUP variant loadable from disk under MS-DOS also additionally
allows the partitioning of Host Drives, which is not possible with GDTSETUP loaded from
the Flash-RAM. Loading GDTSETUP from the Flash-RAM is pretty easy, since there is noth-
ing more required to configure the disk arrays. User's, who have for instance, an NT installa-
tion without a DOS partition, will highly appreciate this Flash-RAM-resident GDTSETUP.
For our example, it is not relevant whether we load GDTSETUP from the Flash-RAM, or from
disk.
Now load GDTSETUP. The first menu asks you to select the desired ICP Controller. In our
example, there is only one ICP Controller installed in the system. Therefore, simply press
<ENTER> and then <F2> to select the Advanced Setup.

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The main menu gives you the following options. As mentioned before, we have to go
through levels 1 to 4 to install the SCSI hard disk (with almost nothing to do on levels 3 and
4).
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Now activate the menu Configure Physical Devices (level 1). A list appears showing all hard
disks found on the ICP Controller’s SCSI channels. If you have a ICP Controller with a differ-
ent number of SCSI channels, the existing SCSI channels are displayed. Note: This screen
will always report all devices that are found to be connected to SCSI-cables, even though
GDTSETUP only allows you to work on Direct Access Devices (and therefore not on tape drives,
DATs, CD ROMs etc.).
The screen shows you:
the channel to which a SCSI device is connected
which SCSI-ID the drive has (the entry SCSI I/O Processor stands for the corresponding
SCSI channel of the ICP Controller. It has the default setting ID 7, as explained in chapter
B)
the initialization status
the SCSI names of the drives
the Read-Write-Status. [RW] = Read + Write
the gross capacity
membership in a Logical, Array or Host Drive
Use the cursor keys nand pto select the drive you wish to initialize. We take the first drive
of channel A in the list. With this drive selected, press <ENTER>.
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(Note: On Channel B, SCSI ID 0, is a drive which has been already initialized before. This is
not relevant for our examples).
The Configure Disk menu appears which shows various options.
For our example we choose the Initialize Disk menu option and press <ENTER>.
The parameters within this menu can be changed by pressing <ENTER> and selecting the
new setting.

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1. Sync. Transfer: Enable
The SCSI-bus allows an asynchronous and a synchronous transfer. Every SCSI device must
be able to perform the first type of transfer, the second one is optional. The advantage of
the synchronous transfer lies in a higher data transfer rate as the signal transfer times on
the possibly long SCSI-cable have no influence on the transfer rate anymore. Two SCSI-bus
participants wanting to exchange data between each other have to check if and how (i.e.,
with which parameters) a synchronous data transfer between them is possible. Therefore,
the mere setting does not automatically enable synchronous data transfer; this mode is
only effective if both devices support it and after they have checked their capability of com-
municating with each other in this mode.
2. Sync. Transfer Rate
The maximum synchronous transfer rate can be limited. This limitation may become neces-
sary if a particular SCSI cabling does not allow the maximum rate the drive and the con-
troller could achieve. In our example, we leave the rate at 20.0 MB/s (for Wide SCSI at 20.0
MB/s and Wide & Ultra SCSI at 40.0 MB/s).
Note: In order to select a transfer rate above 10.0 MB/s the Protocol has to be set to SCSI-III.
3. Disconnect: Enable
The concept of the SCSI-bus allows several participants (8 IDs with 8 LUNs each). All these
participants should be able to use the bus in a manner that causes the least reciprocal dis-
turbance or obstruction. A participant should therefore vacate the bus if he does not need
it. For reasons of performance, it is particularly important to guarantee a high degree of
overlapping of the actions on the SCSI-bus. This high degree of overlapping can be achieved
if a SCSI device is allowed to disconnect, thus leaving the bus to be used by other partici-
pants. If there is only one SCSI device connected to the SCSI-bus, Disconnect should be dis-
abled.
4. Protocol
This can be either SCSI-II or SCSI-III.
If you select SCSI-III make sure, that your hard disk supports this protocol. Most new multi-
GB hard disks support SCSI-III. To enable Ultra (FAST-20) transfer rates (Narrow: 20 MB/s;
Wide: 40 MB/s) SCSI-III protocol is required.
5. Disk Read Cache / Disk Write Cache / Tagged Queues
If a drive supports particular SCSI features you enable them (On).
Note: Most of the modern drives support disk caching (read and write). Some do not sup-
port Tagged Queues.
Press <ESC> to leave the Initialize Disk menu.
GDTSETUP displays a warning on the destruction of all data. This implies two different
evaluations, according to the drive’s current state and the options you have selected:
1.First Initialization of the SCSI Device.
In this case the warning must be taken seriously. If the drive was previously connected to
a different controller (e.g., NCR etc.) and still contains data, this data will be lost now.
2.The SCSI Device was already initialized.
If only internal parameters, such as Disconnect, Synchronous Transfer and SCSI-II op-
tions have been changed, the data on the drive remains intact. Only the function state of
the device is changed.

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Press <Y> and we are back on the main screen of level 1 and see that the initialization-
status of the SCSI device has changed.
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We now leave level 1 (by pressing the <ESC>-key) and are back in the main menu. Now,
with the cursor keys nand pselect Configure Logical Drives and go to level 2 by pressing
<ENTER>.

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The main screen of level 2 appears. Move the selection bar to Create new Logical Drive and
press <ENTER> .
Note: The already existing Logical Drive in this list has no relevance for our example.

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Select the initialized hard disk with the <SPACE>-bar (it becomes marked with an "*") and
press <ENTER>.
For security reasons, you will be asked again if you want to use the selected disk to create a
Logical Drive.
As we are sure of our choice, we confirm with <Yes>. GDTSETUP allows you to limit the
hard disk size for this Logical Drive. This becomes interesting when you configure disk ar-
rays. For this example we use the full capacity and press <ENTER> .

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The dialog box is closed and we are back in the main menu of level 2.
As you can see, we have already created a new Logical Drive of the type Disk. The name of
the Logical Drive is assigned automatically and contains the channel description and the

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SCSI-ID after the "_" . This can serve as a reminder when you install a complex system with
many drives. (Naturally, you may change the name.)
This concludes the installation on level 2. Now press the <ESC>-key to leave this screen.
Since we have only a single disk assigned to a Logical Drive, there is nothing to do in the
Configure Array Drives menu, thus we go directly to the Configure Host Drives menu and have no
Step 4.
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We are now back in the main menu of GDTSETUP and select Configure Host Drive.
The main screen of level 4 appears. Press <ENTER> . A list of available Host Drives is dis-
played. Again, the first entry is not relevant for our example.
At position 1 we find our previously configured Logical Drive. It was automatically trans-
formed into a Host Drive, thus for this example we have nothing to do in this menu.
Press <ENTER> to get a list of possible menu options.