I have observed that many high end routers come with large flash memory , some with up to 128 MB. What exactly that much flash memory required for?

I understand that specious and faster RAM always increases performance, better wifi chips (along with the right antenna) increase data rate and/or range, powerful SoC can take more processing load. But I don't see any usage of >16 MB flash, unless someone decides to use that as a mini desktop computer someday. I have a router with 16 MB flash. After installing all the openwrt packages with features I wish from a router at present, in near future and features I might never use, it still has ~2MB empty space! And the official firmwares from manufacturers often come with linux 2.6.x kernel and very limited feature set compared to what openwrt packages offer. Moreover, router manufacturers often don't encourage people using third party OS. So, why do they bother putting freaking 128MB flash there?

Can someone enlighten me please?

They are using NAND chips, which are very cheap even for GB size.  So why not?  Software always gets bloated especially when hardware manufacturers encourage it.

This is the interesting part, because they seem not to encourage it at all, at least not from open, public perspective. Practically there are <5 802.11AC routers in the openwrt router list. More or less same for dd-wrt. Yet, 802.11ac routers have been existing in the market for over three years. Unless manufacturers are secretly collaborating with openwrt/ dd-wrt developers, I don't see much opening up of drivers or at least integrating them as libraries in open router OS (openwrt,dd-wrt/tomato...). On the other hand, the manufacturers don't seem to bother revolutionizing the routers themselves either.

I guess you are right- when insignificant amount of money can buy significant amount of memory upgrade and thus user attraction, why not?

(Last edited by mmrasheed on 1 Dec 2014, 17:52)

Marketing?

From the manufactuer's view Bigger number = Higher value = Higher sell price. For example, compare a TP-Link to an ASUS or Netgear product with similar chipsets. One of the reasons the TP-Link is cheaper is it always has minimal amount of ram and Flash (there are lots of other variances related to build quality, etc but that's another story).

On the flip side of things I'm more curious as to why they go so low. As stated NAND is dirt cheap (same stuff they use in USB Drives and Memory cards), so why don't they put at least 1 or 2GB in? extra cost would probably be mitigated by the volume of chips that are made at those sizes for other uses...

lol! Perhaps they are following the incremental model, significant upgrade of flash and RAM once in 3-5 years. Or, perhaps they can't find legit answer to the same question, why? Perhaps when the mist of IoT becomes a little clearer, router manufacturers would get the answer to this question, and we will see routers with mac mini config.

Edit: I was checking the TP-link Archer C7 router specs and inside pics. And I completely agree with you. Beside all the gigantic  specs (and chips on board), flash memory seems silly. Couldn't they spare few more cents/router for better marketing and neck to neck fight with the top names!?

(Last edited by mmrasheed on 1 Dec 2014, 18:47)

It may actually be cheaper to get 128MB NAND flash than 16MB (NAND or otherwise).

Things I believe we could use it for… saving more logs longer, backup and perhaps recovery mode when upgrading… even dual boot Long blacklists of evil sites. Hosting the compiler. Of course much flash provides little extra value at the time being since 1) most routers have more limited flash, and OpenWRT will be constructed/configured for little flash in a long time, 2) a USB memory with like 16GB still costs almost nothing, and more internal flash provides few advantages.

I kind of disagree, frankly speaking I prefer the 16MB NOR flash then 1GB NAND flash, for a sysupgrade operation a NOR flash takes 2 mins maximum a NAND flash can take up to 10 mins because of the erase cycle in each flash.

With a large flash you can have more interesting Software installed.
That makes the device useful and interesting for a larger user base.

2MB flash only supports a basic OS/webui (custom Kernel like vxWorks used)
4MB flash allows basic system, extended UI but no "enhanced" features (different functionality requires different images on same hardware)
8MB flash: cover a wide variety of use cases but still limited features (only 2-3 "larger" apps possible)

Some larger apps being:
- Web: OpenVPN (with OpenSSL) and TOR
- Filesystem support (Linux,Windows,Mac,various Network)
- Server: database, files
- Multimedia services: Audio re-streaming, UPnP/DLNA/..., Video server (TVheadend/DVB)
- VOIP software (asterisk,various SIP tools)
- Diagnostic: log facilities...
- File download/sharing support: aria2 , bittorrent+webui ...
- integrate other embedded Boards/Sensors

I think this list will not fit on a 16MB device
While many OpenWrt platforms are space restricted many newly developed Routers are not and have enough CPU power to be useful (dual ARM core like Netgear R8000, pcengines APU1C/D).