Programmer (hardware). In the context of installing firmware onto a device, a programmer, device programmer, chip programmer, device burner, or PROM writer is a device that writes, a.k.a. burns, firmware to a target device's non-volatile memory. 

Typically, the target device memory is one of the following types: PROM, EPROM, EEPROM, Flash memory, eMMC, MRAM, FeRAM, NVRAM, PLD, PLA, PAL, GAL, CPLD, FPGA.

Connection

Generally, a programmer connects to a device in one of two ways.

Insertion

In some cases, the target device is inserted into a socket (usually ZIF) on the programmer. If the device is not a standard DIP packaging, a plug-in adapter board, which converts the footprint with another socket, is used.

Cable & port

In some cases, a programmer connects to a device via a cable to a connection port on the device. This is sometimes called on-board programming, in-circuit programming, or in-system programming.

Transfer

Data is transferred from the programmer to the device as signals via connecting pins. 

Some devices have a serial interface
for receiving data (including JTAG interface).
Other devices communicate on parallel pins, followed by a programming pulse with a higher voltage for programming the data into the device.

Usually, a programmer is controlled via a connected personal computer through a parallel port,
USB port,
or LAN interface.
A program on the controlling computer interacts with the programmer to perform operations such as configure install parameters and program the device,

Types

There are four general types of programmers:

 Automated programmers often have multiple programming sites/sockets for mass production. Sometimes used with robotic pick and place handlers with on-board sites to support high volume and complex output such as laser marking, 3D inspection, tape input/output, etc.
 Development programmers usually have a single programming site; used for first article development and small-series production.
 Pocket programmers for development and field service.
 Specialized programmers for certain circuit types only, such as FPGA, microcontroller, and EEPROM programmers.

History

Regarding old PROM programmers, as the many programmable devices have different voltage requirements, every pin driver must be able to apply different voltages in a range of 025 Volts.
But according to the progress of memory device technology, recent flash memory programmers do not need high voltages.

In the early days of computing, booting mechanism was a mechanical devices usually consisted of switches and LEDs. It means the programmer was not an equipment but a human, who entered machine codes one by one, by setting the switches in a series of "on" and "off" positions. These positions of switches corresponded to the machine codes, similar to today's assembly language.
Nowadays, EEPROMs are used for bootstrapping mechanism as BIOS, and no need to operate mechanical switches for programming.

Manufacturers
For each vendor's web site, refer to "External links" section.
 Batronix GmbH & Co. KG
 BPM Microsystems
 Conitec Datasystems
 Data I/O Corporation
 DediProg Technology Co., Ltd
 Elnec s.r.o
 Elprosys Sp. z o.o.
 halec
 Hi-Lo System Research
 MCUmall Electronics Inc.
 
 Phyton, Inc.
 Xeltek Inc.

See also
Off-line programming
In-system programming
Debug port
JTAG interface
Common Flash Memory Interface
Open NAND Flash Interface Working Group
Atmel AVR#Programming interfaces
PIC microcontroller#Device programmers
Intel HEX – ASCII file format
SREC – ASCII file format
ELF – Binary file format
COFF – Binary file format
Hardware description language

References

External links
Technical information
JEDEC - Memory Configurations: JESD21-C
JEDEC - Common Flash Interface (CFI) Specification, JESD68.01, September 2003.
Intel - Common Flash Interface (CFI) and Command Sets
IEEE Std 1532-2002 (Revision of IEEE Std 1532-2001) - IEEE Standard for In-System Configuration of Programmable Devices
What is the IEEE 1532 Standard?  Keysight Technologies
JEDEC - STANDARD DATA TRANSFER FORMAT BETWEEN DATA PREPARATION SYSTEM AND PROGRAMMABLE LOGIC DEVICE PROGRAMMER: JESD3-C, Jun 1994
JEDEC - JC-42 Solid State Memories

Manufacturers
Batronix GmbH & Co. KG
           BPM Microsystems
                     Conitec Datasystems Inc.
                      Data I/O Corporation
                   Elnec s.r.o.
                  Elprosys Sp. z o.o.
                   Dediprog
 halec
                 Hi-Lo System Research Co. Ltd.
                    MCUmall Electronics Inc.
                Minato Holdings Inc.
                         Phyton, Inc.
                     Xeltek Inc.

Computer engineering
Integrated circuits
Non-volatile memory
Gate arrays