Difference between server & PC

Server is first of all a computer, that is running server software, used to share files, etc. This is just a description of that it provides some services for other computers, users.

The difference in harware construction sometimes is only to make sure this computer (server) will not stuck, when 200 user whant the same file, or checking their mail accounts at the same time. Servers are usualy made using failure resistent components.

It is desirable, that server be stand-alone, because it should be, ideally, ALWAYS available and online. And user may reboot it from time to time.

Of course it should run server operation system, like Windows NT.

Though the main purpose of server is to serve.

You don't build a sever exactly the same way as a pc. Quite often you stick reduntent stuff in it. Like more then one ehternet card, in case one goes down. You also often put more cpus in and more then one harddisk. Really top of the line severs have 4GBs of ram a amount a desktop computer won't need for years. NOS(Network operatying systems) are always differnet from desktop OS. They often have less hardware support, but are more stable. They can use more then one cpu as well. When someone says that they have a sever however, they don't always mean they have a really good computer running in a cooled vault, they just mean they have a computer running some software that gives something to users accessing the system, be it web pages or printer access. Someone wrote a websever that ran on a computer the size of a matchbox, but they still called it a sever.

If you notice when searching for a server there are several main differences resulting from the motherboard.

1) Capable of more memory capacity.
Normal PC's will hold up to 4 memory chips normally while servers will hold up to 8 memory chips normally.
2) Server PC's will support up to 6 and sometimes more hard drives to achieve RAID.
3) Controllers are usually SCSI
4) Capable of supporting Multiple Processors.
5) Bus speed tends to be faster.

Beyond that Servers usually will have a larger power supply and sometimes two power supplies for redundancy or just more capability.

A PC still can function as a server depending on what you want to do with it, but just won't be as capable of expansion down the road.

So what are RAID hard drives for?  I understand that ISPs use them compared to say normal hard drives.

Should I build a server any differently from a PC?  Also, is it possible to run Win NT or win2000 on top of a LINUX server?

celtic, does that mean you can buy special server components like server motherboards with 8 memory slots, dual processor etc?

If you want to build a basic server for personal home use i.e. a file server, print server or a firewall then it doesn't have to much different from an entry level PC.

If it's for corporate use then this is where multi-processor motherboards and RAID arrays come into play.

RAID is not a type of harddisk, it is a software thing that allows you to use lots of harddisk for backing up data(this is very general, they have a ton of raids that work in different ways).

oddbob,
RAID drives are neat, but very expensive.  RAID stands for Redundant Array of Independent Disk.  There are several levels of RAID.  I will describe the extremes and that will give you an idea.

RAID1 is two disk where the data is replicated on both disk.  This allows a switch over to the secondary if the first one goes down, without losing data.  This is similar to mirroring except the controller is writing the data so no data is lost because both disk are written to simultaneously.  If a disk is replaced, the information is copied from one to the other via the RAID controller and its software.(2 20 Gb drives will yield 20Gb of Data)

RAID5 is a set of five disk in use.  Four of the disk are for data and one is for parity.  Parity is a calculated number based on the data on the other four disk.  The RAID controller writes to the disk in sequecne with chunks of data to maximize throughput and data recovery based on sector size.  There are two different types of RAID controllers, Hot-Swappable and Swappable(?).  The Hot-Swappable allows you to swap a drive at any time without shutting down the computer.  The RAID5 controller will then rebuild the data on the drive that was replaced.(5 20Gb drives will yield 80Gb of Data)

Both schemes notify you of a defective drive preventing you from losing information.  The advantage you can see with RAID-5 is that you get 80% of drives as usabel Data, while RAID-1 yields only 50%.  Another less obvious advantage is that RAID-5 is faster writing data because it is not writing data twice, only once with a parity controlled by hardware.

I believe LINUX/WINNT/2000 can be run together, but I have not done it myself.  Provisions can be made with a program like Partition Magic.

As far as buying special mother boards for servers that is correct.  I am not sure of the prices or general availability to the public are, but these are different then your standard mother boards for the basic PC.

I hope this helped you.

Celtics

RAID is a hardware thing, not software. The drives all have to be the same make and size to work with RAID.  Beyond that you need to purchase a RAID controller(hardware) which is where the added cost comes in.  There is software included to do diagnostics and testing, but the control is in the Hardware.

RAID is not a backup system in the true sense.  It is a data recovery system, allowing you to recover from drive failures without losing data.  A backup system is an archival record to a point in time of the entire data on the system.  RAID is up to second data recoverability while a backup is up to a point in time.

I'm inclined to accept celtic's ans, thanks anyway.

Celtic, does a 200 watts PC/server actually consume that much wattage.  Some people get excited about higher wattage PCs, why is that?  

I'm the type who switches off all the lights to save energy but one who leaves my 100/200 watt PC on all day, obviously burning more than a light bulb!

Adjusted pointes for your indepth ans.  Pls post as ans.

Ok maybe so, but for this initial question I was looking at the first response rather than the raid replies.  

Interesting opinions here though....

Server for home use.  1st of all, how many pc's do you want to hook up to it (hub)?  What do you want to do with it (file storage, print q's)?  Are you experienced in any server operating systems ie, novell, NT (a good process to install novell was givin in the netware section)?
Depending on how indepth you want to get, you can take a regular computer, add a network card put the right software on it and make a server or you can add numerous hardware devices and launch the next shuttle, lol, it all depends on what you want to do and all these smart people (I am serious when I say that) can point you in the right direction.  Have a good day.

The bottom line here is

There is no difference in building a server from an "ordinary PC", it is just a question of designing it for the task at hand.

(atleast in my humble opinion)

Just to summarize, the non-technical definition of a "server", IMHO, is a computer that is not used directly by anyone, but rather is accessed over some sort of network by "workstations" which people use or other servers. So generally, it is a computer that no one would sit down and do work at. Of course, there are always exceptions but as I understand it, the definition of a server is completely independent of what hardware it has.

As far as building one for home use, it really depends on what you want to do. If it is just for internal use, ie. file and print sharing then any computer will do, you will just need a network card in it, but you will also need one in your workstations. If you want to protect your data, you will want to implement some sort of backup system. For home use, RAID is a bit excessive, unless it is critical that you have no downtime. This is unlikely, so all you really need is to do tape or CDR backups, or something similar.

If you want your server to do more, like host a webpage or something similar, then you will be more concerned with uptime. In that case, RAID might be more important. Also, depending on how much load (how much work) is put on the server, you might want to go dual processor, or even quad. You will also need more RAM and SCSI HD. All of this quickly adds up in price though, so make sure you know what you are getting into.

Zaphod.

"the definition of a server is completely independent of what hardware it has"

Now THAT sums it all up (IMHO)

*applaudes*

Ok the use of a server at home might be as follows;

1. Host a website once ADSL is out
2. Connect 2-3 other computers in the house to this server to access the Internet
3. Share a printer.
4. Use the server and another PC as a backup device
5. Host games on the Internet like Quake or Unreal Tornoument.

I was thinking of using Intel's product, cant remember what its called, Intel everywhere or something like that.  It allows you to use the existing phone line.  Would this cause problems for a server if a network card is not used?

How much we talking for a RAID system, and a dual processor cabable motherboard?

Also how many websites can you host on a personal web server?

Heh, i used to run that on a 486/DX33-8Mbyte ram and 70Mbyte disk. Hosted about a dozen websites.


(didnt use it as a backup device, and i would have needed 32mbyte to run the quakeserver on it)

Theoretically you can host 64 websites on PWS afaik.

A good raidsystem will cost you a few thousan dollars. (just a _good_ raidcontroller is $4000)

OddBod:

Any PC with decent harddrive space and RAM will do. I currently have a P150 with 128MB RAM and 20GB HDD for a server (I'm running NT 4.0 on it, about to change to Linux). The only add-ons on this server is an extra LPT card ($8) for hosting two printers, and a ZIP drive (to share between my wife and I).

If you are going to use the server to host Q3A games, you will have to meet the requirements for that game, i.e., PII 233, 64MB RAM. Since the game will be hosted (not played) on the server, you will not need a special video card.

Craig

As far as the Intel everywhere or whatever it is called, I don't think that will be compatible with ADSL since I imagine they both use the same frequency band on your phone line. If you have two phone lines, or if you get dedicated DSL, this won't be a problem, but dedicated DSL is pretty expensive. You could also get cable internet. As far as the hardware requirements for the server go, it still depends on what exactly you do with it. If you have maybe 10-100 people accessing your webpage each day and all they do is view it (so there is no advanced forms, or user customization) then just a good desktop would suffice. One thing you might want to consider is that if your webpage is heavily accessed it may have an effect on your internet connection. Also, the A in ADSL means that you can download from the internet faster than you can send to internet. This means that people downloading your page will not have a great download rate. These are all things to keep in mind but, if you are planning to just have a machine that is a server for two machines with backup and all that, as well as some webserving, then all you need is a decent desktop (high PII, lowPIII with decent amount of RAM, probably 128 MB and a good IDE HD. You might want to think about picking up a cheap used tape drive for backups or just use a Jazz drive or something similar.

Zaphod.

if your building a server for home use, don't go crazy.  i have an older clone 200mx with 32 megs of ram.  it's running nt server fine.  also, i've installed novell 4.11 on it too.  it runs fine.  i wouldn't use it for enterprise use, but for just dinking around at home, it's fine.

If you want to host games like Quake, as courtnec said, you need more than jj_mako suggested. If you don't host games, and you have only very low volume websites then the system he described is adequate. It all depends on what you want to do. Running games and applications on the server takes processor and RAM, file sharing and print sharing does not. Neither require RAID, since RAID's primary use is to prevent downtime, which usually isn't that big a deal for home networks. Of course, that doesn't mean you don't want SCSI, since it will generally be faster than IDE, and you can get it pretty cheap if you pick up a used server that some company is getting rid of.

Zaphod.

Wow - everyone has a comment!!

For what it's worth - my opnion of a server is a system which is built from parts which have been tested by the OS supplier and CERTIFIED to run their system.
If you have a look an novell.com and microsoft.com you will find that each has some kind of "approved hardware" list.
Note that configurations are tested and not individual parts.
This testing costs $$$ so when IBM, HP, Compaq or whovever send a PC for testing they make sure it is a system for which parts will be available for a reasonable time - part of the cost of buying a name brand server is the backup in parts etc.
While people can discuss RAID, redundant PSU's etc etc the bottom line is what is YOUR application going to require of a server.
I have installed DEC and IBM servers as well as clone pc's running server apps and have found that in general the name brands run faster and usually come with NIC's etc already set up.
Clones are almost always cheaper, but if you are running a mission critical application I would always use name brand boxes.
My opinion on what you need is some kind of clone system - I've just retired my old server - P150 48MB RAM and 6GB SCSI (Clone) running NT 4 which happily supported 10 users running accounts, our workshop system etc.
If you want something to learn with and experiment on go clone, if you want max uptime, parts availability etc go brand name.

Thanx for listening



BigMark

PC's can be servers
At home I have 3 PC's
1    Win 95, NT Server
2    WIn 98, NT w/s, NT server, Novell Server
3    Win 3.11, Novell Server

I just boot up each one and use it as a PC or server as required.  1 & 3 are Cirix P166 with 96 Mb memory and 2 is a Intel PII 233 with 96 Mb memory.  When I studied for my IIS4 exam I used computer 1 as a web server.

So as you have probably already gathered from the other comments here, the difference between a PC and a server comes from the type of use it is to be put and the size of your network rather than PC or server.

Wow, this question is quite popular.

Maybe a summary of it all would help.

Server/PC: there is no difference. Everything depends on your BUDGET. But in itself there is no difference in building a server or a PC (certainly not for home-use)

RAID:
RAID0: Disk-striping: minimum number of HDD's is 2: Both disks (which have to be the same) are divided into stripes on which data are stored regardless of the physical identity of the HDD. Advantage: speed.
RAID1: Disk-mirroring: Minimum number of HDD's is 2: Data are stored on 1 HDD and 'mirrored' on the other. So Disk2 is an identical copy of Disk1. Advantage: Data-safety: On failure off on of the disks you allways have the other.
RAID5: Disk-striping with parity: minimum number of HDD's is 3. Same as RAID0 but with the advantage of RAID1. All disks are divided into stripes. One part of the stripe is used for parity. 2 parts for data-storage. The parity-part of the stripe allways moves on with each stripe to divide the workload of the disks.

To my humble opinion I found j2's answer the most satisfying.

Kindest regards

"Both disks (which have to be the same)" They do not have to be the same, but in most cases they have to be of "similar size", or else you get a stripeset with the size of (number_of_cells x Size_of_smallest_cell)

(I'm not picking on you, just that to me "the same" means same make/model)

Cheers!

1. stripeset?

2. "Capable of supporting Multiple Processors"

Is this where the Xeon comes in?  So what does this mean, that with 2 xeon processors at 400 mhz each, the comp. will operate at 800 mhz? How does the system not get confused between sharing the work between two processors?

3) Bus speed tends to be faster.

I thought normal bus speed is 100mhz unless you have a pre-historic system running at 66mhz or less?

4. Ok, so RAID actually a setup, an actual hardware drive, or just ordinary hard drives with a special software to make it RAID?

To answer point 2, a computer with multiple processors will use each processor to work on a different task or "thread." For example, one CPU can can handle all of the operating system processing, while the other deals with the application that you have open. On a server, which usually runs some very intensive applications, like a web server or an e-mail server for a large number of people, it can help to have multiple processors so that one can deal with one application while the other deals with the other application. So, the short answer to your question is no, doubling the number of processors does not double performance, it depends a lot on what your computer is doing.

Zaphod.

Ok I need some helping awarding the points.  Who should it go to?

you should award the points to j2.

His answer was the most helpfull and most correct.

Regards.

"1. stripeset?" several harddisks acting as one, you "stripe" the data, placing one stripe on each disk (depending on parity requirements ofr cource)

"So what does this mean, that with 2 xeon processors at 400 mhz each, the comp. will operate at 800 mhz? How does the system not get confused between sharing the work between two processors? " 

No, the computer will run at 400MHz, but will have two CPUs, the OS will divide 'threads' between the different CPUs, so unless the program is written to be multithreading, it wont do you any good to have a SMP (multi processor) system.

The system i am on now is running SMP i have two 500MHz CPU's in it, the way i have set it up is to set the PAM (Processor Affinity Mask) so that i try to move all background service-threads to one CPU and keeping one CPU to run the GUI, this way the system 'never' seems sluggish, even under heavy load.

"I thought normal bus speed is 100mhz unless you have a pre-historic system running at 66mhz or less?"  The PCI bus is still 33MHz.

"Ok, so RAID actually a setup, an actual hardware drive, or just ordinary hard drives with a special software to make it RAID?"  Can be both. However software raid has no advantages over hardware raid (apart from initial cost).