Specifications Dell™ OptiPlex™ GX270 Systems Users Guide
Specifications
Dell™ OptiPlex™ GX270 Systems Users Guide
| Microprocessor | |
|---|---|
Microprocessor type | Intel® Pentium® 4 and Celeron®; design provides for future Dell-supported upgrades. A slower compatibility speed can be set through system setup. |
Level 1 (L1) data cache | 8 KB |
Level 2 (L2) cache | 128-KB, 256-KB, 512-KB, or 1-MB (depending on your computer configuration) pipelined-burst, eight-way set associative, write-back SRAM |
| Memory | |
|---|---|
Type | 333- and 400-MHz DDR SDRAM |
Memory connectors | small form-factor computer: 2 |
Memory capacities | 128-MB, 256-MB, 512-MB, or 1-GB non-ECC |
Minimum memory | 128 MB |
Maximum memory | small form-factor computer: 2 GB |
BIOS address | F0000h |
| Computer Information | |
|---|---|
Chip set | Intel 865G |
Data bus width | 64 bits |
Address bus width | 32 bits |
Interrupt levels | 24 |
BIOS chip | 4-MB |
NIC | Gigabit integrated network interface with ASF 1.0 support as defined by DMTF Capable of 10/100/1000 communication
Off — The computer is not detecting a physical connection to the network or the controller is disabled in System Setup. |
System clock | 800-, 533-, or 400-MHz quad-data rate; 200-, 133-, or 100-MHz (matches external bus speed) |
| Video | |
|---|---|
Type | Integrated chipset video or expansion AGP card |
| Audio | |
|---|---|
Type | AC97 |
Stereo conversion | 16-bit analog-to-digital; 20-bit digital-to-analog |
| Controllers | |
|---|---|
Hard drive | dual-channel Serial ATA, supporting one device per channel |
| Expansion Bus | |
|---|---|
Bus type | PCI 2.2 |
Bus speed | PCI: 33 MHz |
Small form-factor computer | low-profile cards are supported (card size =6.35 cm [2.5 inches] high by 16.76 cm [6.6 inches] long) |
AGP |
|
connector | one |
connector size | 172 pins |
connector data width (maximum) | 32 bits |
bus protocols | 8x/4x modes at 1.5 V |
PCI |
|
connector | one |
connector size | 120 pins |
connector data width (maximum) | 32 bits |
Small desktop computer | two half-length PCI cards (card size = 10.67 cm [4.2 inches] high by 17.65 cm [6.95 inches] long) |
AGP |
|
connector | one |
connector size | 172 pins |
connector data width (maximum) | 32 bits |
bus protocols | 8x/4x modes at 1.5 V |
PCI |
|
connectors | two |
connector size | 120 pins |
connector data width (maximum) | 32 bits |
Small mini-tower computer | card sizes = three PCI slots support cards up to 27.9 cm (11 inches) long, and one PCI slot and the AGP slot support cards up to 22.9 cm (9 inches) long |
AGP |
|
connector | one |
connector size | 172 pins |
connector data width (maximum) | 32 bits |
bus protocols | 8x/4x modes at 1.5 V |
PCI |
|
connectors | four |
connector size | 120 pins |
connector data width (maximum) | 32 bits |
| Drives | |
|---|---|
Externally accessible: | |
Small form-factor computer | one bay for a slimline floppy drive one bay for a slimline CD/DVD drive |
Small desktop computer | one 3.5-inch bay one 5.25-inch bay |
Small mini-tower computer | two 3.5-inch drive bays two 5.25-inch drive bays |
Internally accessible: | |
Small form-factor computer | one bay for a 1-inch-high hard drive |
Small desktop computer | one bay for a 1-inch-high hard drive |
Small mini-tower computer | two bays for 1-inch high hard drives |
| Connectors | |
|---|---|
External connectors: | |
Serial | 9-pin connector; 16550C-compatible |
Parallel | 25-hole connector (bidirectional) |
Video | 15-hole connector |
Network adapter | RJ45 connector |
PS/2 (keyboard and mouse) | 6-pin mini-DIN |
USB | two front-panel and six back-panel USB 2.0–compliant connectors |
Audio | three connectors for line-in, line-out, and microphone; one front-panel connector for headphones |
System board connectors: | |
Primary IDE drive | 40-pin connector |
Secondary IDE drive | 40-pin connector |
Serial ATA | 7-pin connector |
Secondary Serial ATA (not available on the small form-factor or small desktop computers) | 7-pin connector |
Floppy drive | 34-pin connector |
CD drive audio interface | 4-pin connector |
Serial | 12-pin connector for optional 2nd serial port card |
Fan | 3-pin connector |
PCI 2.2 | 120-pin connector |
Front audio | 10-pin connector |
Front panel | 34-pin connector |
| Key Combinations | |
|---|---|
restarts the computer | |
toggles microprocessor speeds on 101-key keyboard (in MS-DOS® real mode only) | |
toggles microprocessor speeds on 102-key keyboard (in MS-DOS real mode only) | |
starts embedded system setup (during start-up only) | |
automatically starts the computer from the network environment specified by the remote boot environment (PXE) rather than from one of the devices in the system setup Boot Sequence option (during start-up only) | |
displays a one-time boot menu that lets the user enter a device for a single boot (during start-up only) | |
launches the utility partition (if installed) during computer start-up | |
launches the hard-drive diagnostics utility during computer start-up | |
| Controls and Lights | |
|---|---|
Power control | push button |
Power light | green light—blinking green in sleep state; solid green for power-on state amber light—blinking amber indicates a problem with an installed device; solid amber indicates an internal power problem (see "Power Problems") |
Hard-drive access light | green |
Link integrity light (on integrated network adapter) | green light for 10-Mb operation; orange light for 100-Mb operation; yellow light for a 1000-Mb (1-Gb) operation |
Activity light (on integrated network adapter) | yellow blinking light |
Diagnostic lights | four lights on the back panel |
Standby power light | AUX_PWR on the system board |
| Power | |
|---|---|
DC power supply: | |
Wattage | small form-factor computer: 160 W |
Heat dissipation | small form-factor computer: 455 BTU/hr |
Voltage | 90 to 135 V at 50/60 Hz; 180 to 265 V at 50/60 Hz |
Backup battery | 3-V CR2032 lithium coin cell |
| Physical | |
|---|---|
Small form-factor computer: | |
Height | 9.0 cm (3.57 inches) |
Width | 31.9 cm (12.54 inches) |
Depth | 35.4 cm (13.93 inches) |
Weight | 6 kg (14 lbs) |
Small desktop computer: | |
Height | 10.6 cm (4.2 inches) |
Width | 38.9 cm (15.3 inches) |
Depth | 43.2 cm (17 inches) |
Weight | 9.9 kg (22 lbs) |
Small mini-tower computer: | |
Height | 42.5 cm (16.7 inches) |
Width | 18.1 cm (7.1 inches) |
Depth | 44.7 cm (17.6 inches) |
Weight | 14.5 kg (32 lbs) |
| Environmental | |
|---|---|
Temperature: | |
Operating | 10° to 35°C (50° to 95°F) NOTE: At 35°C (95°F), the maximum operating altitude is 914 m (3000 ft). |
Storage | –40° to 65°C (–40° to 149°F) |
Relative humidity | |
Operating | 20% to 80% (noncondensing) |
Storage | 5% to 95% (noncondensing) |
Maximum vibration: | |
Operating | 0.25 G at 3 to 200 Hz at 0.5 octave/min |
Storage | 0.5 G at 3 to 200 Hz at 1 octave/min |
Maximum shock: | |
Operating | bottom 40-G half-sine pulse with a change in velocity of 20 inches/sec (50.8 cm/sec) |
Storage | 105-G pulse with a change in velocity of 50 inches/sec (127 cm/sec) |
Altitude: | |
Operating | –15.2 to 3048 m (–50 to 10,000 ft) |
Storage | –16 to 10,600 m (–50 to 35,000 ft) |
Dell™ OptiPlex™ GX260 Systems Users Guide
Technical Specifications
Dell™ OptiPlex™ GX260 Systems Users Guide
| Microprocessor | |
Microprocessor type | Intel® Pentium® 4 and Celeron™ microprocessors. Design provides for future Dell-supported upgrades. A slower compatibility speed can be set through system setup. |
Level 1 (L1) cache | 8 KB |
Level 2 (L2) cache | 1.5– 2.0* GHz processors: 256-KB pipelined-burst, eight-way set-associative, write-back SRAM 2.2–2.6 GHz processors: 512-KB SRAM *Certain 2.0G systems may be upgraded to 512K cache. |
Math coprocessor | internal to microprocessor |
| Memory | |
Architecture | 200- and 266-megahertz (MHz) double-data rate (DDR) synchronous dynamic random-access memory (SDRAM) |
Dual in-line memory module (DIMM) sockets | two non-error checking and correction (non-ECC) |
DIMM capacities | 128, 256, 512 MB, and 1 GB |
Minimum random-access memory (RAM) | 128 MB |
Maximum RAM | 2 GB |
Basic input/output system (BIOS) address | F0000h |
| Computer Information | |
Computer chip set | Intel 845G |
Data bus width | 64 bits |
Address bus width | 32 bits |
Direct memory access (DMA) channels | 7 |
Interrupts | 23 |
Computer BIOS | 4-Mb flash chip |
System bus speed | 400- or 533-MHz quad-data rate; 100- or 133-MHz clock (matches external bus speed) |
Network interface controller | integrated PCI Network Interface with ASF (Alert Standards Format) support as defined by DMTF. |
| Audio | |
Audio type | AC97, Sound Blaster emulation |
Audio controller | Integrated AC97 Codec |
Stereo conversion | 16-bit analog-to-digital; 20-bit digital-to-analog |
Interfaces: | |
Internal | PCI bus/AC97 |
External | stereo line-in minijack, microphone-in minijack, line-out minijack on the rear input/output (I/O) panel; headphones minijack on the front panel |
| Expansion Bus | |
Bus types | PCI 2.2, AGP 2.0, and USB 2.0 |
Bus speed | PCI: 33 MHz AGP: 66 MHz |
Small form-factor computer | one PCI slot and one AGP slot; low-profile cards are supported (card size = 6.35 cm [2.5 inches] high by 16.76 cm [6.6 inches] long) |
Small desktop computer | two PCI slots and one AGP slot; half-length cards are supported (card size = 10.67 cm [4.2 inches] high by 17.65 cm [6.95 inches] long) |
Small mini-tower computer | four PCI slots and one AGP slot (card sizes = three PCI slots support cards up to 27.9 cm [11 inches] long, and one PCI slot and the AGP slot support cards up to 22.9 cm [9 inches] long) |
PCI expansion-card connector size | 120 pins |
PCI expansion-card connector data width (maximum) | 32 bits |
AGP expansion-card connectors | one |
AGP expansion-card connector data width (maximum) | 32 bits |
AGP expansion-card connector size | 172 pins |
AGP bus protocols | 4x modes at 1.5 V |
Memory module connector size | DDR — 184 pins; SDRAM — 168 pins |
| Drives | |
Externally accessible bays: | |
Small form-factor computer | one for a slimline floppy drive one bay for a slimline CD/DVD drive |
Small desktop computer | one bay for a 3.5-inch floppy drive one bay for a 5.25-inch CD/DVD drive |
Small mini-tower computer | two bays for two 3.5-inch floppy drives two bays for two 5.25-inch CD/DVD drives |
Internally accessible bays: | |
Small form-factor computer | one bay for a 1-inch-high IDE hard drive |
Small desktop computer | one bay for a 1-inch-high IDE hard drive |
Small mini-tower computer | two bays for a 1-inch high IDE hard drive |
| Ports | |
Externally accessible: | |
Serial (data terminal equipment [DTE]) | one 9-pin connector; 16550-compatible on the back I/O panel |
Parallel | one 25-hole connector (bidirectional) on the back I/O panel |
Video | 15-hole VGA connector on the back I/O panel |
Integrated network adapter | RJ45 connector on the back I/O panel |
Personal System/2 (PS/2)-style keyboard | 6-pin mini-Deutsche Industrie Norm (DIN) on the back I/O panel |
PS/2-compatible mouse | 6-pin mini-DIN on the back I/O panel |
Universal Serial Bus (USB) | four USB-compliant connectors on the back I/O panel; two on the front panel |
Internally accessible: | |
Primary IDE hard drive | 40-pin connector on PCI local bus |
Secondary IDE hard drive | 40-pin connector on PCI local bus |
Floppy drive | 34-pin connector |
CD drive audio interface | 4-pin connector |
Telephony | 4-pin connector |
Fan | 3-pin connector |
PCI | 120-pin connector |
| Key Combinations | |
restarts (reboots) the computer | |
toggles microprocessor speeds on 101-key keyboard (in MS-DOS® real mode only) | |
toggles microprocessor speeds on 102-key keyboard (in MS-DOS real mode only) | |
starts embedded system setup (during start-up only) | |
automatically starts the computer from the network environment specified by the remote boot environment (PXE) rather than from one of the devices in the system setup Boot Sequence option (during start-up only) | |
displays a one-time boot menu that lets the user enter a device for a single boot (during start-up only) | |
launches the utility partition (if installed) during computer start-up | |
changes boot sequence (during start-up only) | |
| Controls and Lights | |
Power control | push button |
Power lights | green light on power button—blinking green in sleep state; solid green for power on state |
Hard drive access light | green light |
Link integrity light (on integrated network adapter) | green light for 10-Mb operation; orange light for 100-Mb operation; yellow light for a 1,000-Mb (1-Gb) operation |
Activity light (on integrated network adapter) | yellow blinking light |
Diagnostic lights | four yellow and/or green lights on back I/O panel |
Standby power light | AUX_LED on the system board |
| Power | |
DC power supply: | |
Wattage | small form-factor computer: 160 W |
Heat dissipation | small form-factor computer: 455 BTU/hr (average) |
Voltage | 90 to 135 V at 50/60 Hz; 180 to 265 V at 50/60 Hz |
Backup battery | 3-V CR2032 lithium coin cell |
| Physical | |
Small form-factor computer: | |
Height | 9.0 cm (3.57 inches) |
Width | 31.9 cm (12.54 inches) |
Depth | 35.4 cm (13.93 inches) |
Weight | 6 kg (14 lbs) |
Small desktop computer: | |
Height | 10.6 cm (4.2 inches) |
Width | 38.9 cm (15.3 inches) |
Depth | 43.2 cm (17 inches) |
Weight | 9.9 kg (22 lbs) |
Small mini-tower computer: | |
Height | 42.5 cm (16.7 inches) |
Width | 18.1 cm (7.1 inches) |
Depth | 44.7 cm (17.6 inches) |
Weight | 12.7 kg (28 lbs) |
| Environmental | |
Temperature: | |
Operating | 10° to 35°C (50° to 95°F) |
Storage | –40° to 65°C (–40° to 149°F) |
Relative humidity | 20% to 80% (noncondensing) |
Maximum vibration: | |
Operating | 0.25 gravities (G) at 3 to 200 Hz at 0.5 octave/min |
Storage | 0.5 G at 3 to 200 Hz at 1 octave/min |
Maximum shock: | |
Operating | bottom half-sine pulse with a change in velocity of 20 inches/sec (50.8 cm/sec) |
Storage | 27-G faired square wave with a velocity change of 200 inches/sec (508 cm/sec) |
Altitude: | |
Operating | –16 to 3048 m (–50 to 10,000 ft) |
Storage | –16 to 10,600 m (–50 to 35,000 ft) |
Specifications Dell™ OptiPlex™ GX280 Systems Users Guide
Specifications
Dell™ OptiPlex™ GX280 Systems Users Guide
| Microprocessor | |
|---|---|
Microprocessor type | Intel® Pentium® 4; design provides for future Dell-supported upgrades. |
Level 1 (L1) cache | 32 KB |
Level 2 (L2) cache | 1 MB pipelined-burst, eight-way set associative, write-back SRAM |
| Memory | |
|---|---|
Type | 400 & 533 MHz DDR2 SDRAM |
Memory connectors | small form-factor computer: 2 |
Memory capacities | 128 MB, 256 MB, 512 MB, or 1 GB non-ECC |
Minimum memory | dual-channel: 256 MB |
Maximum memory | small form-factor computer: 2 GB |
BIOS address | F0000h |
| Computer Information | |
|---|---|
Chipset | Intel Grantsdale |
Data bus width | 64 bits |
Address bus width | 32 bits |
DMA channels | eight |
Interrupt levels | 24 |
BIOS chip (NVRAM) | 4-Mb |
Memory speed | 400 & 533 MHz |
NIC | integrated network interface with ASF 1.03 support as defined by DMTF. Capable of 10/100/1000 communication:
|
| Video | |
|---|---|
Type | integrated Intel Extreme Graphics or PCI Express x16 DVI video card |
| Audio | |
|---|---|
Type | AC97, Sound Blaster emulation |
Stereo conversion | 16-bit analog-to-digital; 20-bit digital-to-analog |
| Controllers | |
|---|---|
Drives | small form-factor: one serial ATA controller supporting one device and one parallel Ultra ATA/100 IDE supporting two devices per channel with one channel small desktop: one serial ATA controllers supporting one device each and one parallel Ultra ATA/100 IDE supporting two devices per channel with one channel desktop: two serial ATA controllers supporting one device each and one parallel Ultra ATA/100 IDE supporting two devices per channel with one channel. small mini-tower: two serial ATA controllers supporting one device each and one parallel Ultra ATA/100 IDE supporting two devices per channel with one channel mini-Tower: two serial ATA controllers supporting one device each and one parallel Ultra ATA/100 IDE supporting two devices per channel with one channel |
| Expansion Bus | |
|---|---|
Bus type | PCI 2.2 |
Bus speed | PCI: 33 MHz |
Small Form-Factor computer | low-profile cards supported |
PCI | |
connector | one |
connector size | 120 pins |
connector data width (maximum) | 32 bits |
PCI Express | |
connector | one x16 |
connector size | 164 pins |
connector data width (maximum) | 16 PCI Express lanes |
Small Desktop computer | half-length cards supported |
PCI | |
connectors | one or two (depending on purchase) |
connector size | 120 pins |
connector data width (maximum) | 32 bits |
PCI Express | |
connector | one x16 and an optional x1 |
connector size | 120 pins (x16) and an optional 36 pins (x1) |
connector data width (maximum) | 16 PCI Express lanes (x16) and an optional one PCI Express lane (x1) |
Desktop computer | half-height cards supported |
PCI |
|
connectors | two (without card cage) |
connector size | 120 pins |
connector data width (maximum) | 32 bits |
PCI Express |
|
connectors | one x16 |
connector size | 120 pins (x16) |
connector data width | 16 PCI Express lanes (x16) |
Small Mini-Tower | full-height cards supported |
PCI | |
connectors | three |
connector size | 120 pins |
connector data width (maximum) | 32 bits |
PCI Express | |
connector | one x1 and one x16 |
connector size | 36 pins (x1) and 120 pins (x16) |
connector data width (maximum) | one PCI Express lane (x1) and 16 PCI Express lanes (x16) |
Mini-Tower | full-height cards supported |
PCI |
|
connectors | two |
connector size | 120 pins |
connector data width (maximum) | 32 bits |
PCI Express |
|
connectors | one x1 and one x16 |
connector size | 36 pins (x1) and 120 pins (x16) |
connector date width (maximum) | one PCI Express lane (x1) and 16 PCI Express lanes (x16) |
| Drives | |
|---|---|
Externally accessible: | |
Small Form-Factor computer | one bay for a slimline floppy drive |
Small Desktop computer | one 3.5-inch bay |
Desktop computer | one 3.5-inch drive |
Small Mini-Tower computer | two 3.5-inch drive bays |
Mini-Tower computer | one 3.5-inch drive bay |
Internally accessible: | |
Small Form-Factor computer | one bay for a 1-inch-high hard drive |
Small Desktop computer | one bay for a 1-inch-high hard drive |
Desktop computer | one bay for a 1-inch-high hard drive |
Small Mini-Tower computer | two bays for 1-inch high hard drives |
Mini-Tower computer | two bays for 1-inch high hard drives |
| Connectors | |
|---|---|
External connectors: | |
Serial | 9-pin connector; 16550C-compatible |
Parallel | 25-hole connector (bidirectional) |
Video | 15-hole connector |
Network adapter | RJ45 connector |
Optional PS/2 with secondary serial port adapter | small form-factor computer: one 6-pin mini-DIN with a Y-adapter |
USB | two front-panel and six back-panel USB 2.0–compliant connectors |
Audio | three connectors for line-in, line-out, and microphone; one front-panel connector for headphones |
System board connectors: | |
Primary IDE drive | 40-pin connector |
Serial ATA | small form-factor computer: one 7-pin connector |
Floppy drive | 34-pin connector |
Serial | 12-pin connector for optional second serial port card |
Fan | 5-pin connector |
PCI 2.2 | 120-pin connector |
CD drive audio interface | 4-pin connector |
Front audio | 10-pin connector (For the optional audio customer kit) |
Front panel | 40-pin connector |
| Key Combinations | |
|---|---|
If running Microsoft® Windows® XP, brings up the Windows Security window. If in MS-DOS® mode, restarts (reboots) the computer | |
starts embedded system setup (during start-up only) | |
automatically starts the computer from the network environment specified by the remote boot environment (PXE) rather than from one of the devices in the system setup Boot Sequence option (during start-up only) | |
displays a boot device menu that allows the user to enter a device for a single boot (during start-up only) as well as options to run hard-drive and system diagnostics | |
| Controls and Lights | |
|---|---|
Power control | push button |
Power light | green light—blinking green in sleep state; solid green for power-on state amber light—blinking amber indicates a problem with an installed device; solid amber indicates an internal power problem (see Power Problems) |
Hard-drive access light | green |
Link integrity light (on integrated network adapter) | green light for 10-Mb operation; orange light for 100-Mb operation; yellow light for a 1000-Mb (1-Gb) operation |
Activity light (on integrated network adapter) | yellow blinking light |
Diagnostic lights | small form-factor, small desktop, and small mini-tower computers: four lights on the back panel |
Standby power light | AUX_PWR on the system board |
| Power | |
|---|---|
DC power supply: | |
Wattage | small form-factor computer: 160 W |
Heat dissipation | small form-factor computer: 546 BTU/hr |
Voltage | fixed-voltage power supply—110 V at 50/60 Hz manual selection and auto-sensing power supplies—90 to 135 V at 50/60 Hz; 180 to 265 V at 50/60 Hz; 100 V at 50/60 Hz for Japanese computers |
Backup battery | 3-V CR2032 lithium coin cell |
| Physical | |
|---|---|
Small Form-Factor computer: | |
Height | 9.0 cm (3.57 inches) |
Width | 31.9 cm (12.54 inches) |
Depth | 35.4 cm (13.93 inches) |
Weight | 6 kg (14 lbs) |
Small Desktop computer: | |
Height | 10.6 cm (4.2 inches) |
Width | 38.9 cm (15.3 inches) |
Depth | 43.2 cm (17 inches) |
Weight | 9.9 kg (22 lbs) |
Desktop computer |
|
Height | 11.4 cm (4.5 inches) |
Width | 39.9 cm (15.7 inches) |
Depth | 35.3 cm (13.9) inches |
Weight | 10.4 kg (23 lbs) |
Small Mini-Tower computer: | |
Height | 42.5 cm (16.7 inches) |
Width | 18.1 cm (7.1 inches) |
Depth | 44.7 cm (17.6 inches) |
Weight | 12.7 kg (28 lbs) |
Mini-Tower computer |
|
Height | 41.4 cm (16.3 inches) |
Width | 18.5 cm (7.3 inches) |
Depth | 43.9 cm (17.3 inches) |
Weight | 12.34 kg (27.2 lbs) |
| Environmental | |
|---|---|
Temperature: | |
Operating | 10° to 35°C (50° to 95°F) NOTE: At 35°C (95°F), the maximum operating altitude is 914 m (3000 ft). |
Storage | –40° to 65°C (–40° to 149°F) |
Relative humidity | 20% to 80% (noncondensing) |
Maximum vibration: | |
Operating | 0.25 G at 3 to 200 Hz at 0.5 octave/min |
Storage | 0.5 G at 3 to 200 Hz at 1 octave/min |
Maximum shock: | |
Operating | bottom half-sine pulse with a change in velocity of 20 inches/sec (50.8 cm/sec) |
Storage | 27-G faired square wave with a velocity change of 200 inches/sec (508 cm/sec) |
Altitude: | |
Operating | –15.2 to 3048 m (–50 to 10,000 ft) |
Storage | –15.2 to 10,668 m (–50 to 35,000 ft) |
The Four Different Types of Linux Users
The Computer User:
This is a person that feels no emotional ties to FOSS/Linux. The computer is a tool to get the job done and they use Linux because it is the best tool for the job they are trying to accomplish. If Windows or OSX was better suited for the task, then they would be using that instead. They may have no idea of what FOSS or Linux is, they just know their computer works when they need it to. Odds are Linux was installed on their system by friend or relative who is a Linux Advocate or FOSS Extremist who was tried of fixing issues that kept popping up on Windows.
The Dual Booter:
Typically someone who has some computer savvy about them. Odds are they decided to give Linux a try because they just caught an interesting article about a shiny new distro release on Digg or because they know a Linux Advocate who recommended it. They might make a forum post or two to try and solve an issue they are having, but odds are if the distro doesnt "just work" they will start going on about how Linux "isnt ready for the average user" or "will never make it as a desktop operating system". If their Linux install does work, they still keep Windows around because they are a "gamer" or because they need to use a piece of Windows software that does not have a decent FOSS/Linux alternative as of yet.
Linux Advocate:
Someone who uses Linux because they feel it is a superior or more stable operating environment. Typically this is someone who knows their way around the computer a bit and isnt afraid to post on a forum asking a question or get their hands dirty with a bit of terminal code to get their system up and running. While they love the power of FOSS they realize at the same time that the entire world does not work in this manner (although it would be great if it did). They are typically willing to use restricted codecs and closed source video drivers to get the performance and functionality they need out of their system. While it is not uncommon for them to recommend Linux to their family and friends, most times they will even help them get it setup, they realize that some people are happy with Windows and they acknowledge this.
FOSS Extremist:
They use Linux not only because it is fast and stable, but because it is FOSS. They view software that is closed source as something evil that must be conquered or changed for the good of man kind. The know the ins and outs of their system - most times for an FOSS Extremist the GUI is optional. If their hardware does not work right "out of the box" on their favorite distro they are willing to spend hours pouring over manuals and help pages to get it working. They almost constantly preach about the evils of Windows and Apple and take every chance they get to convert those they know to Linux or and FOSS operating system.
Do you think I covered most Linux users here? If not let me know other "types" of Linux users you think there are in the world. If I did cover them all where do you fit into my four different categories? Perhaps you are even a mix of two, personally I find myself somewhere inbetween FOSS Extremist and Linux Advocate depending on my mood.
