SOFTWARE DEVELOPMENT FOR CLOSE-RANGE APPLICATIONS
UNDER CONSIDERATION OF PRESENT STANDARDS
Günter Pomaska
Consultant of Rollei Fototechnic, Braunschweig, Germany
Writing software today is not only the implementation of algorithms in a high level programming language like C
or user Fortran. The final product has to be a userfriendly system running in different environments. The
existing standards for interfaces, graphic concepts or data formats are as important as the algorithms behind. The
digital photogrammetric workstation for close-range applications from Rollei Fototechnic is explained under
consideration of software design and usage of development tools.
Key Words : Software development, software tools, hardware, application software
1. COMPUTER HARDWARE TODAY
1.1 PC TECHNOLOGY i286/i386/i486
Intel introduced the first 16-bit processor in 1978
with it's 8086 processor. In 1979, the Intel 8088
processor contained the same architecture as the
8086 but with an external 8-bit bus. The 20 bit
adressing gives access to 1 MByte memory with 64
KByte segment size.
In 1982, the 1286 offered to adress 16MB of physical
memory and 1 Gigabyte of virtual memory with
64KB segments in the 16-bit Protected Mode. This
machine could perform 2 Mips, 7 times more than the
former 8086. For compatibility with the 8086/88, the
80286 could run in a Real Mode with IMB memory
limitation.
A significant drawback of the 80286 was the 16-bit
barrier, instead of using the 32-bit architecture for far
greater performances. Therefore, the introduction of
the 80386 microprozessor in 1985 with its capability
of linear adressing of 4 Gigabyte physical memory
and 64 Terrabytes virtual memory (swapping of
blocks between RAM and Disk) was a breakthrough
for using PC in a technical environment.
The operation modes of the 80386 start with the Real
Mode for compatibility with the 8086/88 (memory
access to 1 MB), up to ten times faster due to the
faster clock rate. In Protected Mode, the 80386 can
execute a subset of 80286 Protected Mode
instructions (16 MB memory access) or it can run its
own full 32-bit adressing mode with individual
memory segments up to four Gigabyte.
In Virtual 8086 Mode, the 80386 can run multiple
8086/88 programs unchanged and simultaneously.
Due to the higher clock speed, the software runs
eight times faster. Software that implements a set of
virtual machines is called 80386 control program and
is not an operating system. Samples for 80386
control programs are MS Windows/386, Desqview or
VM/386. The Virtual 8086 Mode allows
virtualization of Real Mode applications only.
The advantage of the i486 , available since 1990,
against the 1386 is its higher speed (1386 5 Mips, i486
20 Mips). Including the floating point processor on
board, this microprocessor, fully compatible to the
80386 chip, is the recent hardware standard on a PC
basis.
Competitive sellers of 32-bit microprocessors are for
example Motorola or National Semi Conductor and
other companies.
For photogrammetric applications, only the 32-bit
protected mode is of interest as this operation mode
is the key to perform workstation applications on a
personal computer.
The above given information may answer some of the
common questions why a software package
sometimes is not running under any environment.
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