PS5 could be backward compatible with PS4 games

A new patent hints that Sony's new PlayStation console--presumably the PlayStation 5--could indeed be a full next-generation jump instead of another console refresh.

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According to a Sony patent that's recently been granted by the United States Patent and Trademark Office, the Japanese games-maker is working on backward compatibility features for a new system. This heavily implies that the PS5 will be able to play PS4 games, which is something I said is 100% essential for the PlayStation brand's future. This also strongly suggests the PS5 is a hardware push above the current PS4 family of systems, and unlike the PS4 Pro or Microsoft's approach with the Xbox One X. However, the patent also suggests the PS5 won't be dramatically more powerful than the PS4 or PS4 Pro.

The patent is fairly involved but speaks mostly in plain language, explaining why certain tech is so important to ensure smooth backward compatibility. Essentially what it comes down to is CPU and GPU power and timing discrepancies; for instance, if the PS5's CPU is slower than the PS4's (won't happen), the games will have lots of issues and vice-versa. And yes, PS4 architect Mark Cerny helped invent the patent.

Here's a tidbit from the patent:

"If the CPUs of the new device have lower performance than the CPUs of the legacy device, many errors in a legacy application may arise due to the inability to meet real-time deadlines imposed by display timing, audio streamout or the like. If the CPUs of the new device have substantially higher performance than the CPUs of the legacy device, many errors in a legacy application may arise due to the untested consequences of such high speed operation."

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"FIG. 1 is a block diagram illustrating an example of a central processing unit (CPU) core that may be configured to operate in a backwards compatibility mode in accordance with aspects of the present disclosure."

And here's the patent's abstract, or the main goal and explanation of what the patent is trying to achieve:

"A device may be run in a timing testing mode in which the device is configured to disrupt timing of processing that takes place on the one or more processors while running an application with the one or more processors. The application may be tested for errors while the device is running in the timing testing mode."

I've copied a huge portion of the patent's info below for your perusal, but for now it's safe to say Sony is working on solid backward compatibility features for a new console or device. Whether it's the PS5 or maybe some type of newfangled PlayStation streaming box remains to be seen.

Based on everything said in the patent I think this will apply wholly to a new system and doesn't necessarily link to true PS3/PS2/PS1 disc-based backward compatibility for the PS4. But again, it's entirely possible.

Aspects of the present disclosure are related to execution of a computer application on a computer system. In particular, aspects of the present disclosure are related to a system or a method that provides backward compatibility for applications/titles designed for older versions of a computer system.

Modern computer systems often use a number of different processors for different computing tasks. For example, in addition to a number of central processing units (CPUs), a modern computer may have a graphics processing unit (GPU) dedicated to certain computational tasks in a graphics pipeline, or a unit dedicated to digital signal processing for audio, all of which are potentially part of an accelerated processing unit (APU) that may contain other units as well. These processors are connected to memory of various types, using buses that may be internal to an APU or externally located on the computer's motherboard.

It is common that a set of applications are created for a computer system such as a video game console or smartphone (the "legacy device"), and when a variant or a more advanced version of the computer system is released (the "new device") it is desirable for the applications of the legacy device to run flawlessly on the new device without recompilation or any modification that takes into account the properties of the new device. This aspect of the new device, as contained in its hardware architecture, firmware and operating system, is often referred to as "backwards compatibility."

Backwards compatibility is often achieved through binary compatibility, where the new device is capable of executing programs created for the legacy device. However, when the real-time behavior of the category of devices is important to their operation, as is in the case of video game consoles or smartphones, significant differences in the speed of operation of a new device may cause it to fail to be backwards compatible with respect to a legacy device. If the new device is of lower performance than the legacy device, issues that prevent backwards compatibility may arise; this is also true if the new device is of higher performance, or has different performance characteristics when compared to the legacy device.

It is within this context that aspects of the present disclosure arise.

Aspects of the present disclosure describe computer systems and methods which may allow applications written for a device to have a higher degree of backwards compatibility when running on a second device that is binary compatible (in that the programs written for the first device will execute on the second device) but has different timing characteristics (in that the programs written for the first device will execute at different rates on the second device, and therefore errors in operation may arise). The second device could potentially be a variant or a more advanced version of the first device, and could potentially be configured in a "backwards compatibility mode" where the features and capabilities of the second device more closely approximate those of the first device.

In implementations of the present disclosure, a timing testing mode is created for the first device. This mode creates timings not found (or not typically found) on the device, with the result that when an application is run in this mode, errors in synchronization between hardware components (such CPU, GPU, audio and video hardware) or between software components (such as application processing or OS processing) occur in ways that are not possible or not common on the device during normal operation. Once these errors in synchronization are detected, the application software may be fixed to eliminate or alleviate them, increasing the likelihood that the application will execute properly on a second device with different timing characteristics, i.e. the application will have a higher degree of backwards compatibility on the second device with respect to the first device. As the capabilities of the second device may not be known (e.g. it may be a future device that does not exist yet), it is of benefit to have a great variety to the timings available in the timing testing mode.

In implementations of the present disclosure, in the timing testing mode, the operating system may configure the hardware in a certain state (e.g. at a specific operating frequency not found in normal operation of the device). Additionally, in the timing testing mode, the operating system may alter the hardware configuration as the application is running, or perform various processing (e.g., processes that compete for system resources or preempt the application processing) as the application is running.

In implementations of the present disclosure, the testing may be performed on hardware different from the device. For example, using ICs selected to run at a greater operating range than a consumer device will allow testing modes not available on the consumer device.