Lp0 on fire
Encyclopedia
lp0 on fire is a semi-obsolete error message still generated on some Unix
and Unix-like
operating systems in response to certain types of printer
errors. lp0
is the Unix device handle for the first line printer
, but the error can be displayed for any printer attached to a Unix/Linux system.
, installed around 1959 at the Lawrence Livermore National Laboratory
, modified with an extended fusing oven to achieve a print speed of one page per second. In the event of a printing stall, and occasionally in normal operation, the fusing oven would heat paper to combustion, which was aggravated by the fact that if the printer continued to operate, it would essentially stoke the oven with fresh paper at high speed. There is, however, no evidence of the "lp0 on fire" message appearing in any software of the time.
As the technology matured, most large printer installations consisted of large drum printers
, a type of impact printer which could print an entire line of text at once through the use of a high speed rotary printing drum. It was thought that in the event of a severe jam, the friction
of paper against the drum could ignite either the paper itself, or, in the event of a dirty machine, the accumulated paper and ink dust in the mechanism. However, it is unclear if this ever happened, as there are no surviving reports of friction-related printer fires.
The line printer employed a series of status codes, specifically ready, online, and check. If the online status was set to "off" and the check status was set to "on," the operating system would interpret this as the printer running out of paper. However, if the online code was set to "on" along with the check code also set to "on" this would mean that the printer still has paper, but is suffering an error, and is still running. Due to the potentially hazardous conditions which could arise in early line printers, Unix displayed the message "on fire", which would serve to motivate any system operator viewing the message to go and check on the line printer immediately.
and laser printer
s are nowhere near as flammable as their mainframe ancestors, the lp
device code in all sorts of POSIX
-compliant operating systems retained this legacy
message. As printer drivers and support improved, this error condition could be trapped and handled appropriately, and as a result, most Unix/Linux users today have never encountered the "on fire" message. However, the message is still present in many kernels
, especially with legacy parallel port
device support, and continues to baffle users to this day.
The "on fire" message is also present in other components, often to a humorous effect. For example, in some kernels' CPU code, a CPU thermal failure
could result in the message "CPU#0: Possible thermal failure (CPU on fire ?)."
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
and Unix-like
Unix-like
A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....
operating systems in response to certain types of printer
Computer printer
In computing, a printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a...
errors. lp0
Lp (Unix)
The lp command is used on many Unix-like systems to assign jobs to printer queues. The name derives from "lineprinter", though it has become the commonly used command for any sort of printer...
is the Unix device handle for the first line printer
Line printer
The line printer is a form of high speed impact printer in which one line of type is printed at a time. They are mostly associated with the early days of computing, but the technology is still in use...
, but the error can be displayed for any printer attached to a Unix/Linux system.
History
The probable origin of the "on fire" message was the late 1950s, when high speed computerized printing was still a somewhat experimental field. The first documented fire-starting printer was a Stromberg-Carlson 5000 xerographic printerLaser printer
A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and multifunction printers , laser printers employ a xerographic printing process, but differ from analog photocopiers in that the image is produced...
, installed around 1959 at the Lawrence Livermore National Laboratory
Lawrence Livermore National Laboratory
The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...
, modified with an extended fusing oven to achieve a print speed of one page per second. In the event of a printing stall, and occasionally in normal operation, the fusing oven would heat paper to combustion, which was aggravated by the fact that if the printer continued to operate, it would essentially stoke the oven with fresh paper at high speed. There is, however, no evidence of the "lp0 on fire" message appearing in any software of the time.
As the technology matured, most large printer installations consisted of large drum printers
Line printer
The line printer is a form of high speed impact printer in which one line of type is printed at a time. They are mostly associated with the early days of computing, but the technology is still in use...
, a type of impact printer which could print an entire line of text at once through the use of a high speed rotary printing drum. It was thought that in the event of a severe jam, the friction
Friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and/or material elements sliding against each other. There are several types of friction:...
of paper against the drum could ignite either the paper itself, or, in the event of a dirty machine, the accumulated paper and ink dust in the mechanism. However, it is unclear if this ever happened, as there are no surviving reports of friction-related printer fires.
The line printer employed a series of status codes, specifically ready, online, and check. If the online status was set to "off" and the check status was set to "on," the operating system would interpret this as the printer running out of paper. However, if the online code was set to "on" along with the check code also set to "on" this would mean that the printer still has paper, but is suffering an error, and is still running. Due to the potentially hazardous conditions which could arise in early line printers, Unix displayed the message "on fire", which would serve to motivate any system operator viewing the message to go and check on the line printer immediately.
Legacy
While modern inkjetInkjet printer
An inkjet printer is a type of computer printer that creates a digital image by propelling droplets of ink onto paper. Inkjet printers are the most commonly used type of printer and range from small inexpensive consumer models to very large professional machines that can cost up to thousands of...
and laser printer
Laser printer
A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and multifunction printers , laser printers employ a xerographic printing process, but differ from analog photocopiers in that the image is produced...
s are nowhere near as flammable as their mainframe ancestors, the lp
Lp (Unix)
The lp command is used on many Unix-like systems to assign jobs to printer queues. The name derives from "lineprinter", though it has become the commonly used command for any sort of printer...
device code in all sorts of POSIX
POSIX
POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...
-compliant operating systems retained this legacy
Legacy code
Legacy code is source code that related to a no-longer supported or manufactured operating system or other computer technology. The term can also mean code inserted into modern software for the purpose of maintaining an older or previously supported feature — for example supporting a serial...
message. As printer drivers and support improved, this error condition could be trapped and handled appropriately, and as a result, most Unix/Linux users today have never encountered the "on fire" message. However, the message is still present in many kernels
Kernel (computing)
In computing, the kernel is the main component of most computer operating systems; it is a bridge between applications and the actual data processing done at the hardware level. The kernel's responsibilities include managing the system's resources...
, especially with legacy parallel port
Parallel port
A parallel port is a type of interface found on computers for connecting various peripherals. In computing, a parallel port is a parallel communication physical interface. It is also known as a printer port or Centronics port...
device support, and continues to baffle users to this day.
The "on fire" message is also present in other components, often to a humorous effect. For example, in some kernels' CPU code, a CPU thermal failure
Computer cooling
Computer cooling is required to remove the waste heat produced by computer components, to keep components within their safe operating temperature limits.Various cooling methods help to improve processor performance or reduce the noise of cooling fans....
could result in the message "CPU#0: Possible thermal failure (CPU on fire ?)."
See also
- PC LOAD LETTERPC Load LetterPC LOAD LETTER is a technology meme, originally a printer error message, which has grown into popular culture as a reference to a confusing or inappropriate error message.-Explanation:...
- Halt and Catch FireHalt and Catch FireHalt and Catch Fire, known by the mnemonic HCF, refers to several computer machine code instructions that cause the CPU to cease meaningful operation...
- Not a typewriterNot a typewriterIn computer science "Not a typewriter" or ENOTTY is an error code defined in the errno.h found on many Unix systems. This code is used to indicate that an attempt has been made to use a non-TTY device as a TTY device.- Details :...
- HTTP 418Hyper Text Coffee Pot Control ProtocolThe Hyper Text Coffee Pot Control Protocol is a protocol for controlling, monitoring, and diagnosing coffee pots.HTCPCP is specified in the jocular RFC 2324, published on 1 April 1998. Although the RFC describing the protocol is an April Fools' Day joke, it specifies the protocol accurately enough...