Why are PS4 and PS5 unable to read PS1 or PS2 discs?



They are clearly able to emulate the games based on the PS1 and PS2 games being available on the digital storefront.

Edit: Thank you all for the informative replies.

In: Technology

>Why are PS4 and PS5 unable to read PS1 or PS2 discs?

For the same reason a VHS player isn’t able to read an SD card. It’s not built for that kind of application. The PS4’s and PS5’s drives are physically unable to read CDs, only Bluerays and DVDs.

Former game developer here,

Those games may be ports, not emulations. Emulation isn’t trivial, and there likely isn’t an emulator that shipped with the system. Even if there were, the hardware likely couldn’t emulate the older platforms in a performant manner.

PS1 and some PS2 disks are based on the CD standard. The drive in a PS4 (and I assume PS5) doesn’t read CDs. Among other things it’s only equipped with lasers for DVD (650nm) and Blu-ray (450nm).

CD, DVD and BluRay all use different lasers with different wavelengths. A lot of commercial players like the ones you get for computers or media players does come with multiple lasers that can read all disk formats. However PlayStation have chosen to save some cost by only including one laser. There are also some other differences in the tracking mechanism which makes them incompatible. They used the tracking of the grove in the CD to prevent illegal copying of the disks but this made the hardware a bit more complicated which they did not add to the later DVD and BluRay players in the later versions.

The “system” costs money to put it in. It needs special drivers. Also, the physical media is different throughout the generations. You’d need 3-5 lasers to read the disks.

Another major issue that you might not have considered is that CdS have a sampling rate of 44.1khz and blue ray have a sampling rate of 96 khz so not only would you need different lasers for reading you would also need different digitizing circuits and probably different filters for both. That would get very pricey very quickly.

A lot of useful replies relating to the disc reading technologies, but there’s another reason, even if emulation is possible, it takes quite a toll on the hardware,.

Since there’s competition, they’d rather choose a master of one instead of jack of all trades approach.

Also, as technology grows, there are a lot of changes in a console/computer/smartphone architecture, which further complicates emulation beacause the build platform (instruction sets, 8/16/32/64 bits, number of cores, gpu and cpu hardware, etc).

Several reasons. But the main ones are quite simple.

Fully emulating a console so it works with all discs would be difficult. Games they control can be modified to work (assuming they use emulation in the first place – they might be ports)

They don’t make any money from you if you use existing games.

The disc producers aren’t able to recreate the same data they used for those discs as they do with current models, the PS4 and PS5.


Main reason: Different CPU architectures.

Example: Moving to a completely different country and trying to read the news paper in their language with no prior lingual experience of that country.

Imagine the code of the PS1 games being one language and the code of the PS5 games being another language.

They do this on purpose because they have something on the system called Playstation Now, which requires you to sign up for a monthly subscription in order to use it. It’s about making money, plain and simple.

They can, Sony just doesn’t let you via software lock. They want you to pay for Playstation now

The discs on all PS systems are different and sometimes even for the same system, people should remember certain PS1 discs not working on their compatible PS2. After PS3 the standard was the use of Blueray discs that allowed for much more actual data to be stored at a higher fidelity. But also allowed for complete backwards compatibility, I think there were multiple disk readers in use at that point.

tldr; it’s not worth the cost and headache to develop and support the functionality.

To break it down further:

1. As disc technologies developed data was packed smaller and tighter to fit more onto the discs. Each one requires different lasers with different resolutions built into the drives to read the data.
2. As consoles developed the code or language behind them changed. To read and understand the code from an earlier model requires translation (the emulator). It’s an oversimplification but you could compare it to if you only speak English and you want to talk to someone who only speaks Spanish you would need a translator of some kind in the middle to listen to one language, convert it to the other language, and back and forth. You need to find or build that translator (time and money), using it will consume resources (processing power, memory, heat), and it’s very easy for an ‘incomplete’ translation to occur (bugs, bugs, bugs).
3. Support and development costs now go up with each increase in complexity of the above two. There are more people you need to pay, more hardware you have to buy, you have more possible points of failure, more software to debug and a pile of ancient games you’re now stuck supporting long past their end of life, all for a dubious ‘value’ that realistically the vast majority of your consumers are going to ignore, or treat it as a curiosity. And you end up having to deal with somebody’s mother on a Twitter tirade who finds a copy of Atlantis from the PS at a garage sale and wants it to work on their new PS5 so their toddler can play a game.
4. Margins are already slim on consoles, sometimes sold at a loss so the company can get them into as many peoples hands as possible on a bet they’ll make up for that on the games. They need to show a profit or they go under. The money earned from the sale of those old games went bye-bye long ago, either in profits or development of new systems and new games. The added cost and risk don’t make sense for the limited value the functionality is going to offer. It makes more sense to redevelop or remaster the popular games and sell them for a nominal fee for the people that are serious to about wanting to play it. They get a little money back to support the development and they can tighten their support focus considerably which makes for a much stronger product and a better experience for the consumer (ie. you and me).

Surely the PS4/PS5 dont use the exact same cpu/instruction set/gfx hardware as the PS1/PS2??? (Would reaaaally suck if they did!)
AFAIK the ps2 could only play PS1 games because its I/O chip was the same as what the ps1 used as a main cpu, the cpu of the ps2 bring the Emotion engine (EE). The ps1/ps2 games would be calling instructions that the later consoles wouldn’t understand to execute. Emulation is just that…..done via software.
otherwise, Its like putting an NES cart into a SNES and expecting it to work. Completely impossible.

Same reason they removed the ability for PS3’s to read PS2 discs after just one year – it’s expensive to implement backwards compatibility, and they crunched the numbers and decided it’s smarter from a financial standpoint to remove that capability to reduce the cost of the console and sell more units.

PS5’s are backwards compatible with PS4’s because from the PS4 gen onward, game consoles are basically just PC architecture in a smaller space, so there isn’t a ton of work that needs to be done to allow them to play the last-gen games (same reason your PC games from 3 years ago don’t stop working when you upgrade from a GTX 1070 to an RTX 3070).

PS3 had a vastly different architecture than current-gen systems; the PS2 had a vastly different architecture from that; and the PS1 had yet another different type of architecture.

Having said that – it’s totally *doable*. All PS3’s can play PS1 discs because it’s just software emulation, and later in the PS3’s life cycle, Sony developed a PS2 software emulator, which is what the “PS2 Classics” games you can buy on the PlayStation Network run on. Thing is, the PS2 software emulator isn’t super widely compatible, which is why they never unlocked the ability for it to boot games from an inserted disc – they validate the games’ functionality on the emulator, patch any issues, and then release the game to purchase on the PSN store; validating EVERY PS2 game in that capacity would be expensive and time-consuming.

In fact, the PS1 software emulator built into the PS3 **cannot** play certain PS1 discs – for example, *Tomb Raider* and *Tomb Raider II* can’t be played from a physical disc in any PS3; but Sony patched the games and re-released them on the PSN store, so you *can* play them on a PS3, you just have to buy them from PSN.

PS3 games are a different beast entirely. The PS3’s architecture was very complex, and emulating it is very difficult. You’ll hear people refute this by saying PS3 emulation on PC is a thing, but here’s the problem with that – yeah, it’s *a thing*, and there are a handful of games that work flawlessly…but there’s a large chunk of games that don’t work at all, and the majority of the games that *do* work have some issues (ranging from minor to game-breaking) that Sony wouldn’t be willing to let slide on an officially-supported system.

Someone else mentioned the CD reading thing, and that’s a possibility too – I don’t know what kind of UHD Blu-Ray drive is in the PS5, and I don’t know if it has a CD laser or not. **If it doesn’t have a CD laser, then it is physically impossible for a PS5 to read a PS1 disc, or any CD-based PS2 game** (though it wouldn’t have any trouble with the majority of PS2 games were DVD-based). Missing hardware isn’t something you can patch in!

***TL;DR*** – it costs a lot of money and Sony crunched the numbers and decided it isn’t worth the investment.

PS1 discs had a special wobble made into them to prevent piracy, the wobble protected the data area while writing audio data into a normal pattern that could be read by other drives.

In order to read that disc they need to add emulation or hardware into the PS4. This is no problem for them.

The reason why they don’t is they want to create an app store so they can resell the games source code. So rather than getting a free emulator or a $30 emulator they can charge $30 per game.