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Vol. 6: September 1998:
SCSI
vs. EIDE, Cheap P2-450 and a Junk Modem
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09-27-1998: Hard Drives, Chapter One
Greetings once again!
I have had a request for more Hard Drive
information. I don't really have too much to say about them right now, but I
will offer some purchasing advice. First, if you are in the market for a new
HD, you must consider your applications and intended use of the drive. Use the
list below to help you decide which major technology would be your best bet:
In this case, your budget will be better served with an economical EIDE HD.
Western Digital used to be one of the best brands to get, but now, I recommend
Seagate
Medalist drives for budget use, and Medalist Pro for higher end apps in well
ventilated cases. There are many others, and their price reflects a relative
comparison of their quality and features. Maxtor drives have also come around
lately with better speed and reliability. If you want a little better speed,
look for a 7200 RPM or faster HD instead of the 5400 or slower models. Nearly
every IDE HD today is capable of at least PIO Mode 4 or DMA Mode 2, which
provide up to a 16.6 MB/second bus transfer rate. The newest drives are all
UDMA compatible, for a rate of 33 MB/sec, almost the 40MB/sec of UWSCSI. It
can't hurt to get a UDMA one as they are fully backward compatible all the way
to PIO Mode 0 of 3MB/sec. But in Windows NT, they almost require a busmaster
driver from the MB manufacturer or chipset vendor for speeds above PIO Mode 2,
so be careful here or your performance will be less than expected.
In the last case, SCSI is the way to go, although it is not without cost.
First, an adapter card is required. I prefer Adaptec
SCSI cards, and the 2940 series is excellent for home or business use.
Secondly, SCSI HD's cost far more than EIDE HD's. I paid $750 for a SCSI-I 105
MB HD back in early 1990, and a top of the line SCSI HD today can easily exceed
even that price! Again, there is a good reason why one HD of a given capacity
is perhaps hundreds of dollars more than another: Speed! The 10,000 RPM
Seagate Cheetahs are among the world's fastest PC mass storage devices, and no
EIDE drive can approach them. SCSI hard drives also come in larger capacties
than their EIDE counterparts, and are often very reliable, since they are
designed for heavy server type use. When buying a SCSI drive, first consider
whether a modest 7200 RPM model will suffice, or if you really require a 10,000
RPM drive. Then, determine your interface requirements: UltraSCSI (20 MB/sec),
UltraWideSCSI (40 MB/sec), or Ultra2WideSCSI. All of these are SCSI-III
implementations, and provide increasing bandwidth for demanding applications, up
to 80MB/sec for the U2W drives. The interface adds to the cost of both the HD
and the adapter card, so choose wisely here. There are also even higher-speed
interfaces such as Fiber Channel that are used in some servers, but we will skip
that for now. SCSI HD's perform much faster in Windows NT than an EIDE HD due
to NT's support for only up to PIO Mode 2, although busmaster drivers for your
particular MB can alleviate this major bottleneck and must be considered
essential if your system supports them. SCSI HD's handle multiple requests
better, and also load the host CPU less, so they are more ideal for a server
environment. You can also chain 15 or so devices to each SCSI port, which is a
plus where large amounts of storage are needed. The cons are, that it is not
nearly as easy as EIDE to install and setup, partly due to the required
termination of SCSI busses and many different SCSI connectors and modes to
contend with. All for now on this topic. Comments invited!
What is this you say? Fast? P2? Cheap?!? Those words just don't belong
together! They didn't, at least, until Intel put out this little gem of a CPU
called the Celeron
300A. It turns out that they have the same basic CPU core as a Pentium
II-450 MHz unit, except with a different L2 cache setup. The 128K of L2 cache
is on the CPU die itself and runs twice as fast as that in a real P2-450. So,
although the cache is only 128K instead of 512K, IF the Celeron 300A were
running at 450 MHz, it's performance still can slightly better the PII-450. The
Celeron 300A is multiplier locked at 4.5 times the fronstside bus frequency
(FSB) which is the memory bus speed of normally 66 MHz. If you put this Celeron
on an Abit BH6 motherboard,
with good quality PC100 SDRAM, and setup the CPU Soft Menu in the BIOS to run at
4.5x100 MHz, you'll have quite a screamer of a PC! Lots of folks have done
this, including myself, although there is definitely NO guarantee of success!
On this MB, also in the BIOS you can tweak the CPU core voltage up in .05 volt
increments to help increase stability at the higher frequencies. I have mine up
.05 volt to 2.05 volts (the CPU is rated for up to 2.1v normal operation) and it
is running stable so far, even at 2.00 volts it was fine. Going to 463 MHz
though had resulted in a single crash so I'm back to 450, which is incredible
enough as it is. If you want more info on this, let me know. The pricing is
about $180 for the CPU and $125 for the MB. Don't forget the SDRAM either!
I was attempting to replace an old Zoom 14.4 internal faxmodem with a brand
new, internal, USR 56K faxmodem today in a customer's system. The old Zoom was
functioning, and jumpered to COM1. Much to my dismay, the new USR that *I* told
her to purchase (NOT a Winmodem!!), came WITHOUT the jumper blocks for port and
IRQ! The pins were never soldered into the PCB. The instructions were still
silkscreened on the back of it as to how to select them. Putting it in a slot
in that fashion, resulted in no active COM ports detected at all. No problem I
thought, I'll whip out the soldering iron and jumper them myself. OK, set to
COM1, IRQ4. MSD detects the port and the 16550AF on it. Great! BUT all
terminal programs, in DOS and Windows 3.11, don't get any response from that
port at all when I send AT commands, and no modem is detected in Windows!
Change to COM2/IRQ3. Still no result! After much fumbling with the manuals,
none of which mentioned DOS or 3.1 (other than view the online manual which was
useless) I finally gave up after two hours of struggling with it. I tried every
option for the onboard serial ports with no luck, and I installed the software
on the CDROM that came with it. But it didn't have a setup program like some
jumperless NIC's do. Back it goes to the store!
How USR/3Com could
release such a product, and claim on their Web site that that exact model is DOS
compatible, when it doesn't even have any jumpers or setup program, is beyond
me. BTW I checked the model number on the box and card, and although the card
looks radically different than the online or box photos, the model number is
correct and it has a DSP so it is not a Winmodem as I know them. It also
responds as a COM port but not as a modem. So, from now on, I will be very wary
of their new internal products. Yet one more reason to buy an EXTERNAL unit.
:-)
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