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Q: I've seen many discussions about the use of symmetric multiprocessing
(SMP) in Windows NT. Many users favor it, but many say that it's actually slower
than using one processor. Which is correct?
Both sides are correct. Many factors enter into the use of SMP. Most
systems use the Intel SMP configuration (MPS 1.4), but many use OEM-specific
hardware abstraction layers (HALs) optimized for specific motherboards. The
latter systems tend to work better than the generic MPS 1.4 HALs. In the race to
be different, a board manufacturer will often add or change features that are
not compatible with the MPS 1.4 specification. These changes can diminish the
SMP performance.
In both standard and OEM-equipped SMP machines, the ultimate performance
depends on which application you're using. SMP balances a load symmetrically
(i.e., across all processors). The specific thread characteristics of the
application affect the load balancing. If the application is not thread aware
(which usually means the vender never tested the application on an SMP machine),
an SMP machine will not perform as well as a single-processor machine. Screen 1
shows an application (U-Lead's Photoimpact SE version 3.0) that is poorly
threaded. Notice that the workload does not appear to be symmetrical; in fact,
the CPUs appear to be antagonistic toward one another (i.e., the thread bounces
from one CPU to the other). In contrast, Screen 2 shows an application (Picture
Publisher for NT, which unfortunately was never developed into a full product)
that is very thread aware. The CPUs are in total synchronization and complete
the work much faster than a single-processor machine.
Caution: A friend recently purchased a dual 200MHz Pentium Pro with
a SuperMicro motherboard. He added an Intel Pro 10/100 NIC and decided to
repartition his hard disk. NT saw only one CPU. When he removed the Intel NIC
and installed a 3Com XL card, the system recognized both CPUs. Be aware that
certain NICs can conflict with the Advanced Programming Interrupt Controller
(APIC) logic in the SMP machines.
Q: How do image backups compare to standard file backups? Is this a way
for backup vendors to get us to buy new software?
Mainframes have used image backups for many years, but file backups are
more recent. In general, an image backup works with the sectors on a disk and is
independent of the sector content. An image backup includes information about
partition tables, file tables (FAT, MFT, etc.), and the Master Boot Record. File
backups contain information about files and their attributes. In a file backup,
you can selectively restore individual files, whereas in an image or sector
backup, you have to basically restore the entire drive.
Both types of backups have advantages. The file backup lets you restore
individual files and directories but will not regenerate a drive. The image
backup lets you boot to a set of floppies and restore the contents of a tape,
thus regenerating your drive. However, the size of the drive you restore to must
be at least equal to the size of the drive that you back up. In fact, an image
backup works best when you use identical drives. In all cases, you need to
perform a low-level format on the drives to optimize the restore. You do not
need to partition or format the recipient drive. As you might expect, you can't
do an incremental sector backup, so image backup is better for true disaster
recovery and file backups are better for individual file restoration. As of this
writing, only ARCserve and ULTRABAC offer both image and file backup software
for NT.
Q: My colleague wants to use a print server on a small NT LAN. He claims
he can set up the print server as a TCP/IP device, which will offer great
advantages to the LAN. What is a print server, and how do you configure it as a
TCP/IP device?
Print servers are small devices that connect directly to a network hub or
switch. I am aware of only servers that function with 10Base-T and 10Base-2
connections. The print server I have the most experience with is the Axis 560.
This device has two parallel connections and one serial connection. You simply
power the device after you connect it to the switch or hub. From this point, the
setup becomes an NT and print-server issue. On the NT side, you need to add
Microsoft TCP/IP Printing under the Services tab of the Network applet and FTP
under the Internet Information Server Installation applet.
Step one: Place a printer on the first parallel port (PR1), and print a test
page. This page will most likely give you the printer's current settings. The
one to notice is the IP address, which is 192.36.253.80. Unless you have a
router or some means of accessing the device, you need to change the device's IP
address.