Chapter 6. System compatibility

3.Sends the EOI

4.Waits one I/O delay

5.Enables the interrupt through the Set Interrupt Enable Flag command

Hardware interrupt IRQ9 is defined

as the

replacement interrupt

level

for the casc

Program interrupt sharing is implemented

on IRQ2, interrupt hex 0A.

The

following process

maintain compatibility with the IRQ2

used by

IBM Personal Computer

products:

1. A device drives the interrupt request active on IRQ2 of the channel.

2. This interrupt request is mapped in hardware to IRQ9 input on the second interru

3.When the interrupt occurs, the system microprocessor passes control to the IRQ9 interrupt handler.

4. This interrupt

handler performs an EOI command to the second interrupt controller a

to the IRQ2

(interrupt hex 0A) interrupt handler.

5. This IRQ2 interrupt handler, when handling the interrupt, causes the device to re request before performing an EOI command to the master interrupt controller that f the IRQ2 request.

Diskette

drives and

controller

 

 

 

The following figures

show

the reading,

writing, and formatting capabilities of the di

 

 

 

 

 

Figure

17. 3.5-inch diskette drive reading, writing, and formatting capabilities

 

 

 

 

 

 

 

 

 

Diskette

drive type

 

720

KB Mode

 

1.44 MB Mode

 

 

 

 

 

 

 

 

 

 

1.44

MB

drive

 

RWF

 

 

RWF

 

 

 

 

 

 

 

 

 

 

2.88

MB

drive

 

RWF

 

 

RWF

 

 

 

 

 

 

 

 

 

 

Copy protection The following methods of copy protection might not work in systems using

1.44MB diskette drive.

Ÿ Bypassing BIOS routines

– Data transfer rate: BIOS selects the proper data transfer rate for the medi

– Diskette

parameter

table: Copy protection, which creates its own diskette parame

not work

in these

drives.

Ÿ Diskette drive controls

–

Rotational

speed: The

time

between

two events in a diskette drive is a functio

–

Access time: Diskette

BIOS

routines

must set the track-to-track access time for

 

of media

that are

used

in the

drives.

– ‘Diskette change’ signal: Copy protection might not be able to reset this signal.

ŸWrite-current control: Copy protection that uses write-current control does not work,

controller selects the proper write current for the media that is being used.

Hard disk drives and controller

Reading from and writing to the hard disk is initiated in the same way as in IBM products; however, new functions are supported.

Chapter 6. System compatibility23

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Image 31
IBM 6268, 6288, 6278 manual Hard disk drives and controller, Drive type 720 KB Mode MB Mode
Page 30 Page 32

6278, 6268, 6288 specifications

The IBM 6278, 6288, and 6268 are part of IBM's extensive lineup of mid-range computers, specifically tailored for business environments in the late 1980s and early 1990s. These systems were designed to handle substantial data processing tasks, facilitating efficient business operations with robust performance and reliability.

The IBM 6278 was notable for its high-performance capabilities, making it suitable for a variety of applications ranging from transaction processing to complex computations. One of the main features of the 6278 was its multiprocessing capability, which allowed it to run multiple tasks concurrently. This was achieved through a combination of advanced hardware and software that optimized performance and resource allocation.

Similarly, the IBM 6288 was recognized for its versatility and scalability. This system incorporated enhanced memory management and was capable of handling larger workloads than its predecessors. The 6288 was designed with user-friendly interfaces and supported various input/output devices, making it easier for organizations to integrate into existing IT infrastructures. Additionally, it provided improved connectivity options, essential for modern networking needs at the time.

The IBM 6268, on the other hand, offered a balance between cost and performance, appealing to smaller businesses or those with less intensive data processing requirements. Despite being less powerful than the 6278 and 6288, the 6268 still managed to include essential features such as reliable data storage, effective processing speed, and compatibility with IBM's extensive software ecosystem.

All three models utilized IBM's proprietary operating systems, which were well-known for their robustness and security features. They were built with technologies such as error detection and correction, ensuring the integrity of data processing tasks. The architecture of these systems also allowed for easy upgrades, enabling businesses to expand their capabilities without a complete overhaul of their IT infrastructure.

In summary, the IBM 6278, 6288, and 6268 represented a significant advancement in mid-range computing technology during their era. Their main features encompassed multiprocessing, scalability, and user-friendly interfaces, making them valuable assets for businesses seeking reliable and efficient computing solutions. These systems laid the groundwork for future innovations in business computing, and despite their age, they remain a significant part of IBM's legacy in the computing industry.
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