made active participants in increasing system performance. It did have the effect of making an MCA version of a peripheral card significantly more expensive than its ISA counterpart. So while these ad-hoc manufacturer-specific solutions were effective, they were not standardized, and there were no provisions for providing interoperability. This drew the attention of the VESA consortium and resulted in a proposal for a voluntary and royalty-free local bus standard in 1992. An additional benefit from this standardization (beyond the primary goal of greater graphics card performance) was that other devices could also be designed to utilize the performance offered from VLB; notably, mass-storage controllers were offered for VLB, providing increased hard-disk performance. VLB bandwidth depended on the CPU's bus speed: It started at 100 MB/s for CPUs with a 25 MHz bus, increased to 133 MB/s at 33 MHz and 160 MB/s at 40 MHz, and reached 200 MB/s at 50 MHz. Implementation A "VLB slot" itself is an additional edge connector placed in-line with the traditional ISA or EISA connector, with this extended portion often colored a distinctive brown. The result is a normal ISA or EISA slot being additionally capable of accepting VLB-compatible cards. Traditional ISA cards remain compatible, as they do not have pins past the normal ISA or EISA portion of the slot. The reverse was also true VLB cards are by necessity quite long in order to reach the VLB connector and were reminiscent of older full-length expansion cards from the earlier IBM XT era. The VLB portion of a slot looks similar to an IBM MCA slot, as indeed it is the same physical 116-pin connector used by MCA cards, rotated by 180 degrees. The IBM MCA standard had not been as popular as IBM expected, and there was an ample surplus of the connector, making it inexpensive and readily available. Limitations The VESA Local Bus was designed as a stopgap solution to the problem of the ISA bus's limited bandwidth. As such, one requirement for VLB to gain industry adoption was that it had to be a minimal burden for manufacturers to implement, in terms of board re-design and component costs; otherwise, manufacturers would not have been convinced to change from their own proprietary solutions. As VLB fundamentally ties a card directly to the 486 processor bus with minimal intermediary logic (reducing logic design and component costs), timing and arbitration duties were strongly