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Revision as of 02:57, 6 October 2023

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m (→‎Links: Amazing Tek 4052 and 4054 vector demos from Monty McGraw - he doesn't mention licence terms nor offers a contact method so I didn't target any video in particular)
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The storage tube display allows the screen to retain images drawn to it, eliminating the need for frame-buffer memory. This allows the resolution to be as high as the hardware can handle, which is 1024 by 1024 logically (i.e. DAC resolution) but limited by the physical layout of the screen to 1024 by 780. It also allows the machine to dedicate all of its memory to the programs running on it (as opposed to partitioning off a section for the buffer), an important consideration at the time when memory was expensive and scarce.
The storage tube display allows the screen to retain images drawn to it, eliminating the need for frame-buffer memory. This allows the resolution to be as high as the hardware can handle, which is 1024 by 1024 logically (i.e. DAC resolution) but limited by the physical layout of the screen to 1024 by 780. It also allows the machine to dedicate all of its memory to the programs running on it (as opposed to partitioning off a section for the buffer), an important consideration at the time when memory was expensive and scarce.


Released in 1978, the 4952 came with a full 32 kB of RAM for $9,795 ($44,500 in 2022 dollars) and could be expanded to 64 kB for another $1,995 (2022: $9,070) for a total cost of $11,790 (2022: $53,600).
Released in 1978, the 4952 came with a full 32 kB of RAM for $9,795 ($46,100 in 2023 dollars) and could be expanded to 64 kB for another $1,995 (2023: $9,400) for a total cost of $11,790 (2023: $55,500).


The '''4054''' is a version of the 4052 built around the 19" screen from the [[4014]] terminal rather than the 11" screen from the [[4012]], increasing display resolution to 4,096 by 3,072. The 4052 and 4054 can display a limited amount of refreshed graphics. This is done by lowering the beam current of the writing gun so it does not trigger the threshold for stored display. The 4054 also had an Option 30 to display an extensive amount of refreshed graphics that used a [[wikipedia:Signetics 8X300|Signetics 8X300]], an early RISC-like microprocessor. There was also an Option 31 CRT with a special multi-layer phosphor to display the refreshed graphics in orange, against the stored graphics in green. The Option 30 was originally what was known at Tek as a "G-job", an unofficial project by Steve Rintala, which was eventually approved by management.  
The '''4054''' is a version of the 4052 built around the 19" screen from the [[4014]] terminal rather than the 11" screen from the [[4012]], increasing display resolution to 4,096 by 3,072. The 4052 and 4054 can display a limited amount of refreshed graphics. This is done by lowering the beam current of the writing gun so it does not trigger the threshold for stored display. The 4054 also had an Option 30 to display an extensive amount of refreshed graphics that used a [[wikipedia:Signetics 8X300|Signetics 8X300]], an early RISC-like microprocessor. There was also an Option 31 CRT with a special multi-layer phosphor to display the refreshed graphics in orange, against the stored graphics in green. The Option 30 was originally what was known at Tek as a "G-job", an unofficial project by Steve Rintala, which was eventually approved by management.  


In early 1980s, Tektronix introduced the 4052A and 4054A facelift models, changing from ROMs with patch ROMs to EPROMs for the firmware, and replacing the discrete GPIB software implementation with a [[TI9914]] GPIB controller for higher GPIB performance.  
In early 1980s, Tektronix introduced the 4052A and 4054A facelift models, changing from ROMs with patch ROMs to EPROMs for the firmware, and replacing the discrete GPIB software implementation with a [[TMS9914]] GPIB controller for higher GPIB performance.  


==Architecture ==
==Architecture==
Unlike the [[4051]], which is based on an 8-bit [[wikipedia:Motorola 6800|Motorola 6800 CPU]], the 4052 CPU is based on four [[wikipedia:AMD Am2900 | AMD 2901 4-bit bit-slice processors]] used together to make a single 16-bit processor. The processor is microcoded to emulate a 6800 so it can run the 4051 firmware, written in 6800 assembler, with minimal changes. The original goal of the project was to run 8 times faster than the 4051. This was to be achieved by three "factors of 2": First, the processor clock is 2 MHz, compared to the 1 MHz of the 4051 (the 2 MHz was set by the speed of the EPROMs initially used to hold the microcode). Second, the memory is 16 bits wide instead of 8, so two bytes can be accessed in a cycle, theoretically doubling the memory access speed. Finally, the data and code address spaces are separate (Harvard architecture) so program fetch of the next instruction can in principle be overlapped with processing data from the previous instruction.  
Unlike the [[4051]], which is based on an 8-bit [[Motorola 6800]] CPU, the 4052 CPU is based on four [[Am2901]] 4-bit bit-slice processors used together to make a single 16-bit processor.
The processor is microcoded to emulate a 6800 so it can run the 4051 firmware, written in 6800 assembler, with minimal changes.  
The original goal of the project was to run 8 times faster than the 4051.  
This was to be achieved by three "factors of 2": First, the processor clock is 2 MHz, compared to the 1 MHz of the 4051 (the 2 MHz was set by the speed of the EPROMs initially used to hold the microcode).  
Second, the memory is 16 bits wide instead of 8, so two bytes can be accessed in a cycle, theoretically doubling the memory access speed.  
Finally, the data and code address spaces are separate (Harvard architecture) so program fetch of the next instruction can in principle be overlapped with processing data from the previous instruction.  


However, the 4051 firmware was written for the 8-bit 6800 processor so the 16-bit memory access is rarely of any benefit. The overlapping of instruction and data fetch was complicated to implement and was abandoned for the first version of the product. The result was a system with between 2 and 3 times the performance of the 4051.  
However, the 4051 firmware was written for the 8-bit 6800 processor so the 16-bit memory access is rarely of any benefit.  
The overlapping of instruction and data fetch was complicated to implement and was abandoned for the first version of the product.  
The result was a system with between 2 and 3 times the performance of the 4051.


Early in the project, it was proposed that the 6800-assembler-coded implementation of 48-bit floating-point arithmetic used in the 4051 firmware be implemented in microcode, but Tek management vetoed the idea until it became obvious that the performance goals would not be met without it. So, late in the project, the floating-point operations were implemented in microcode by adding new opcodes in gaps in the 6800 opcode map, and the firmware was rewritten to use the new opcodes instead of calling the floating-point subroutines. The result was about a 30-times improvement in speed over the 4051. This was because graphics operations are floating-point intensive − every move or draw requires two multiplies and two adds to convert from the user's coordinate space to screen coordinates. Other numeric-intensive operations such as matrix calculations benefited as well.
Early in the project, it was proposed that the 6800-assembler-coded implementation of 48-bit floating-point arithmetic used in the 4051 firmware be implemented in microcode.
However, Tek management vetoed the idea until it became obvious that the performance goals would not be met without it.  
So, late in the project, the floating-point operations were implemented in microcode by adding new opcodes in gaps in the 6800 opcode map, and the firmware was rewritten to use the new opcodes instead of calling the floating-point subroutines.  
The result was about a 30-times improvement in speed over the 4051.  
This was because graphics operations are floating-point intensive − every move or draw requires two multiplies and two adds to convert from the user's coordinate space to screen coordinates.  
Other numeric-intensive operations such as matrix calculations benefited as well.


==See Also==
==See Also==
Retrieved from "https://w140.com/tekwiki/wiki/Special:MobileDiff/86156"

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