Old Computers
Old Personal Computer Hardware SERVERS
- Processors
- The Elements
- Number of Cores
- How many physical CPU inside the processor
- Number of Threads
- How many virtual CPU working. This is shown in the Task Manager.
- This terms of threads originated from Intel since they developed the ‘Hyper Threading Techonology’ which delivers two threads per physical core.
- NOTE These are Hardware Threads, not software threads used in programming languages
- CPU Speed
- How fast it takes to execute instruction
- Is important for single running applications
- Not important for server as they have many applications. Even then, a single Server applications normally use parallel programming.
- The Cache
- Enables the CPU to retrieve recently used information quickly
- In most cases, the more the cache, the fastar the CPU.
- The Front Side bus (FSB)
- Connection between CPU and Northbridge
- Intel doesn’t use FSB, but uses DMI instead
- Unit in GT/s
- The System Memory
- Number of Cores
- For server, it is good to use XEON due to:
- It’s reliability, low heat and power consumption.
- It is meant to run 24 hours.
- Contrary to popular belief Xeon is not MORE powerful than conventional processor. It’s main advantage is reliability, e.g. It has some other improved reliability features such as ECC memory
- The Elements
- Operating Systems
- Windows
- Windows Server 2008 R2 (July 2009)
- Windows Server 2008 (February 2008)
- Windows Server 2003 (April 2003)
- Network Cards (NIC – Network Interface Card)
- The first thing to check is the number of ports
- Typically it’s either single or dual port
- Meaning how many Ethernet cables can go in
- The next thing to check is it’s connection
- If it say PCIe only that means it is PCIe x1 and compatible with all PCIe slots (X1,X4,X8,X16)
- Another thing to check is it’s bandwidth, they are:
- Ethernet or 10BASE-X
- Only supports up to 100Mbps or 1.25MBps
- Old Technology
- Fast Ethernet or 100BASE-X
- Support up to 100Mbps or 12.5MBps
- Old Technology
- Gigabit Ethernet or 1 GbE
- Supports up to 1000bps or 1Gbps = 125MBps
- Backward compatible
- Can use same CAT5 Cables and connect to 10/100 hardwares
- However, it causes the new equipment to be slower
- 1GBe Ethernet has 5 Varieties in physical layer standards which are
- Ethernet or 10BASE-X
Name | Medium | Specified distance |
1000BASE‑CX | Twinaxial cabling | 25 meters |
1000BASE‑SX | Multi-mode fiber | 220 to 550 meters dependent on fiber diameter and bandwidth[2] |
1000BASE‑LX | Multi-mode fiber | 550 meters[3] |
1000BASE‑LX | Single-mode fiber | 5 km[3] |
1000BASE‑LX10 | Single-mode fiber using 1,310 nm wavelength | 10 km |
1000BASE‑ZX | Single-mode fiber at 1,550 nm wavelength | ~ 70 km |
1000BASE‑BX10 | Single-mode fiber, over single-strand fiber: 1,490 nm downstream 1,310 nm upstream | 10 km |
1000BASE‑T | Twisted-pair cabling (Cat‑5, Cat‑5e, Cat‑6, or Cat‑7) | 100 meters |
1000BASE‑TX | Twisted-pair cabling (Cat‑6, Cat‑7) | 100 meters |
- TOE (TCP Offload Engine)
- New Network cards especially the 1GbE types have TOE (TCP offload engine). What this does is that it has a processor which processes various TCP protocols such as the 3-way handshake which is supposedly to be done by the processor.
- The purpose is to free up processor speed
- Hard Disk
- Interface
- Hard disk commonly interfaces with the PC using a serial bus interface.
- The most common interfaces:
- SATA
- Cheaper because it does not use a built in processor for controlling head position unlike SAS
- SAS (Also known as SCSI)
- Faster and more reliable
- SATA
- Some Hard disks have SED feature (Self Encrypting Device). This is for security purpose
- Hot plug
- A property of a hard disk which can plugged out when the server is running. This avoids server downtime when a hard disk change is required (due to faulty hard drive and etc). Hot plug hardwares cost more
- RAID
- Raid stands for (Redundant Array of Inexpensive Disks). The advantages of RAID
- High Data Reliability and Availability
- Ease of combining hard disk space
- Improve Speed
- Raid Controllers
- When RAID is selected, a RAID controller needs to be installed. For dell, this is called the PERC (PowerEdge Raid Controller).
- Types of RAID Controllers:
- Software RAID Controller
- Hardware RAID Controller
- RAID Numbers:
- 0 (Stripping)
- 2 Hard disks mirrors each other not for redundancy.
- It Doubles data transfer rate, theoretically, but in real life the gains are around 10%
- Improves Performance
- Minimum 2 Drives
- 2 Hard disks mirrors each other not for redundancy.
- 1 (Mirroring)
- 2 Hard disks mirrors each other
- Advantage
- Highest Reliability
- Disadvantage
- Size is limited by the drive with smallest size
- Minimum 2 Drives
- 2 (Bit Level Stripping with Hamming Code parity drives)
- Improve data integrity and reliability
- Obsolete
- Minimum 3 Drives
- 3 (Byte Level Stripping with dedicated parity drive)
- Hardly Used
- Minimum 3 Drives
- Same advantage
- 4 (Block Level Stripping)
- Hardly Used
- Minimum 3 Drives
- 5 (Block level stripping with distributed party)
- Commonly Used
- Advantages
- Provides Redundancy up to one hard disk failure
- Increase Disk Size to (DriveSize x (Number of Drives – 1))
- Disadvantage
- If more than 1 hard disk fail, ALL data are LOST
- Minimum 3 Drives
- 6 (Block level stripping with double distributed parity)
- Needs at least 4 drives
- Tolerates up to two failures
- Minimum 4 Drives
- 10 (Mirroring without parity and block level stripping)
- Is a combination of RAID 1 and RAID 0
- Works in Spans
- Each span will mirror one another (Like Raid 1)
- The upper span works like RAID 0
- Works in Spans
- Advantage
- Speed and Reliability Combined
- Disadvantage
- Less disk space compared to RAID 5
- Is a combination of RAID 1 and RAID 0
- 0 (Stripping)
- Raid stands for (Redundant Array of Inexpensive Disks). The advantages of RAID
- Interface
- Motherboard / Chipset
- DTE/DCE
- DTE – Data Terminal Equipment, Ends a communication line (The processing node)
- DCE – Data Communications Equipment, in the middle of communication line (The bridge)
- PCI Slots (Peripheral Component Interconnect)
- Conventional PCI
- 1991
- 33/66 MHz
- 6 types of slots
- 3.3V 32 Bit
- 5V 32bit
- 3.3V 64 Bit
- 5V 64 bit
- Universal 32 bit
- Universal 64 bit
- 32 bit PCI slots can be used in 64 bit slots
- Conventional PCI
- PCI-X
- 1999
- 66/133 Mhz
- 3.3V 64 Bit
- Faster than Conventional PCI
- Conventional PCI cards can be used on PCI-X slots
- Supports Multi Drop
- PCI Express / PCIe
- 2002
- Formerly known as 3GIO
- Have 4 types of slots
- X1, X4, X8, X16
- The smaller slots can fit in larger slots. That is why some hardware just specify itself as PCIe which means it is PCIe x1 and can fit in all slots
- A typical motherboard will have these slots
- Server Rack
- The most common server rack is the 19” rack. It is specified in EIA , CEA and IEC standards
- Typical rack servers are around 17 to 18”. The racks are mounted by a slide
- Ethernet
- Is a physical layer LAN technology which is defined in the IEEE standards. LAN is a network limited by geography
- The standards
- IEEE 802.3 (Also called Wired Ethernet or Simply referred to as Ethernet)
- IEEE 802.11 (Commonly referred to as Wifi)
- IEEE 802.16 (Commonly referred to as Wimax
- RAM (Random Access Memory)
- What is RAM?
- RAM is a type of Computer Storage. The word random-access means that data can be read anytime without going through a sequential process.
- However, today this has become a name only, modern DRAMs use burst mode reading which is sequential in nature but fast. SRAM however, still works in a RANDOM access way
- RAM are Volatile
- When power is lost, data is lost in the RAM.
- Static (SRAM) vs Dynamic (DRAM)
- SRAM is faster and more expensive. It is often used as cache memory for the CPU
- Don’t need to know much about this other than when buying a CPU.
- DRAM is slower and typically used as computer memory.
- DRAM is the most common RAM Type.
- DRAM Formats (these are just how the memory is designed)
- SIMM (Single Inline Memory Module)
- Old Technology
- 32Bit
- RIMM (Rambus inline Memory Module)
- Old Technology between SIMM and DIMM
- DIMM (Dual Inline Memory Module)
- MOST COMMON FORMAT
- Typically around 4-5 Inches length
- Replacement Technology for SIMM
- 64Bit
- Twice more Pins than a SIMM, Faster than SIMM
- The number of Pins in DIMM is determined by the specification type (e.g. DDR2, DDR3, SDRAM)
- SDRAMs (The old type) -168 PINS
- DDR1 (OR DDR SDRAM) -184 PINS
- DDR3 and DDR2 -240 PINS
- SO-DIMM (Small outline dual in-line memory module)
- Used is system with limited space such as Laptops
- Typically 2.5-3 Inches Length
- Number of Pins
- DDR2 – 200 Pins
- DDR3 – 204 Pins
- DDR4 – 256 Pins
- DRAM Asynchronous vs Synchronous
- Asynchronous DRAM
- Not suitable for high speed systems
- Synchronous DRAM
- Since it’s synchronous, it waits for Clock Signal. This is why Speed is rated in MHz rather than in Nano seconds
- Common types of DIMM
- SDRAM (Synchronous Dynamic Random Access Memory)
- First Generation, Slower than DDR
- Write 1 Words per clock cycle
- DDR SDRAM [MOST COMMON TYPE WHEN OPENING ON A LAPOP OR DESKTOP]
- DDR Stands for Double Data Rate
- Unlike SDRAM, it write 2 words per clock cycle
- Evolution of DDR SDRAM
- DDR1 (Also just called DDR SDRAM)
- DDR2
- DDR3
- DDR(X)’s are not backward or forward compatible with each other, meaning if a mother board supports DDR1 it will not Support DDR2 and Vice Versa
- DDR Standard is set by JEDEC
- On a Memory, a typical annotation would be
- DDRx-yyyy – x is the DDR version, yyyy is the data rate of the memory measured in MT/s (Mega Transfer Per Second).
- This is essentially the Clock Speed which is usually advertised.
- PCx-yyyy – x is the DDR Version, yyyy is the peak transfer rate measured in MB/s. MB/s = MT/s x 8
- For example, PC2-6400 means it is a DDR2 Ram with Speed of 6400/8 = 800 MHz
- Brands
- Good Ones
- Crucial
- Corsair
- Kingston
- G Skill
- Bad Ones
- RAM Clock Speed
- Should generally choose the highest RAM Speed supported by the mother board
- One should not use RAM of different speeds as this causes instability
- Number of PINS
- This is important when purchasing a RAM as the number of PINS need to match the motherboard
- Typically the following rules apply:
- SDRAMs (The old type) have 168 PINS
- DDR1 (OR DDR SDRAM) has 184 PINS
- DDR3 and DDR2 has 240 PINS
- Single or Pair?
- Pair is better as it allows Dual Channel
- 2x2 GB RAM is better than 1x4GB RAM
- Power Supply Unit (PSU)
- A computer PSU’s job is to convert mains AC to low-voltage regulated DC power
- Specification Standards
- ATX
- Most Common
- BTX
- Number of Pins
- The number of Pins required would depend on the motherboard
- 24 Pins
- Connectors
- Typical Power supplies have several connectors, and this is usually standard
- P1 - PC Main Power Connector
- This goes to the Motherboard
- Has either 20 or 24 Pins
- Power supply with 24 Pin connector can be used on motherboard with 20 pin connector
- Some 20 pin connectors have an additional 4 pin connector (referred to as 20+4), which can be put side by side to create a 24 pin connector
- 4 Pin Peripheral Power Connector
- Goes to various disk drives
- Black wire is ground
- Yellow is 12v, Red is 5v
- Can be any label
- Serial ATA Power Connectors
- Used for Hard drives and Optical Drives
- 15 pins inside
- Can be of any label (P2 to p15)
- Floppy Power Connector
- For floppy drives
- Is a small connector with a protrusion on the pin between red and black
- 4 pins – yellow(12v), black (ground), black (ground), red (5v)
- Can be of any label (p2 – p15)
- ATX 4-Pin Power supply connector
- Can be of Any label (p2 – p15), typically p2
-
Used to provide 12VDC to the processor voltage regulator, which is on the mother board.