## An adapter to put a SRAM chip in the Boot ROM socket of a Realtek RLT8019AS network card. The RTL8019AS ethernet ASIC includes support for writeable flash/eeprom memory devices in the boot ROM socket. The signal to flash these devices is the same MEMW signal that RAM uses, so this means it's possible to use a RAM chip in this socket as an upper memory block. However, many network cards use a DIP28 socket that supports only 16 Kb of ROM memory, and where the MEMR and MEMW signals are tied low and high respectively, instead of being connected to the bus signals. This adapter allows to install a SRAM chip in DIP32 package on those cards with a "brain dead" socket. The adapter reroutes MEMW, MEMR and the additional address lines to the C2 connector, so that they can be wired to the corresponding signals on the card edge connector of the network card. With the adapter you can have up to 64Kb of UMBs, mapped in memory according to the RTL's configuration settings for the ROM socket base. However, the setting to enable memory writes is not "persistant"; it's not set based on the configuration EEPROM contents, it needs to be specifically set "on", presumably by the program used to flash new contents. Therefore you simply can't "set and forget it" for use as upper memory. You have to load the zero-resident enabler [RTL2UMB.EXE](https://github.com/Astrowallaby/PaleozoicPC-stuff) from config.sys before a UMB provider program such as USE!UMBS.SYS. During execution the program stuffs the necessary registers on the card to enable writes and exits.