Update EIP-7870: Lowers requirements for a "Full Node".md

EIPS/eip-7870.md

@@ -42,21 +42,26 @@ Without a shared understanding of target hardware specifications:
 
 Node operators typically run both an **Execution Layer (EL)** client and a **Consensus Layer (CL)** client on the same machine. The specifications below assume the combined resource usage of both.
 
-| Node Type               | Storage   | Memory | CPU Cores / Threads | **PassMark CPU Rating** | Bandwidth Download / Upload |
-| ----------------------- | --------- | ------ | ------------------- | ----------------------- | --------------------------- |
-| **Full Node**           | 4 TB NVMe | 32 GB  | 4c / 8t             | ~1000 ST / 3000 MT      | 50 Mbps / 15 Mbps           |
-| **Attester**            | 4 TB NVMe | 64 GB  | 8c / 16t            | ~3500 ST / 25000 MT     | 50 Mbps / 25 Mbps           |
-| **Local Block Builder** | 4 TB NVMe | 64 GB  | 8c / 16t            | ~3500 ST / 25000 MT     | 100 Mbps / 50 Mbps          |
+| Node Type               | Storage     | Memory | CPU Cores / Threads | **PassMark CPU Rating** | Bandwidth Download / Upload |
+| ----------------------- | ----------- | ------ | ------------------- | ----------------------- | --------------------------- |
+| **Full Node**           | 512 GB NVMe | 32 GB  | 4c / 8t             | ~1000 ST / 3000 MT      | 50 Mbps / 15 Mbps           |
+| **Attester**            |   4 TB NVMe | 64 GB  | 8c / 16t            | ~3500 ST / 25000 MT     | 50 Mbps / 25 Mbps           |
+| **Local Block Builder** |   4 TB NVMe | 64 GB  | 8c / 16t            | ~3500 ST / 25000 MT     | 100 Mbps / 50 Mbps          |
 
 *Approximate single-thread (ST) and multi-thread (MT) PassMark CPU scores. For example, a PassMark ST rating of 3500 and an MT rating of 25000 typically corresponds to upper mid-range server CPUs circa 2024–2025.*
 
 ## Rationale
 
 ### Storage
 
-- **Recommended**: 4 TB NVMe M.2 drive with:
+- **Recommended**: NVMe M.2 drive with:
   - **Sequential R/W**: 7,000 MB/s
   - **Random 4K R/W**: Up to 1,000,000 IOPS
+  - 512GB - 4TB of free space (depending on node type)
+- **Why 512GB for Full Node?**
+  - A node that just wants to trustlessly follow the tip of the chain and execute contracts at tip does not need to retain any history beyond finality.  This includes old receipts, blobs, blocks, and transactions.  If you prune all of that plus prune all state older than last finality, the disk space needed should fit in under 512GB.  Some clients may need additional space to actually do the pruning.
+- **Why 4TB for Attesters and Block Builders?**
+  - In order to build an archive node or help someone sync the chain from genesis, history needs to be available on the network.  It is recommended that Attesters and Local Block Builders maintain full history so they are able to properly serve these things to the network.  It isn't strictly necessary, but if everyone drops history then the network breaks.
 - **Why NVMe over SATA?**
   - NVMe drives have significantly higher throughput and lower latency than SATA SSDs.  
   - Drives without DRAM (DRAMless) or with QLC flash are not advised, due to lower endurance and potentially lower sustained performance.
@@ -115,7 +120,7 @@ Node operators typically run both an **Execution Layer (EL)** client and a **Con
 ### Quick Reference Summary
 
 - **Full Node**  
-  - **Storage**: 4 TB NVMe  
+  - **Storage**: 512 GB NVMe  
   - **RAM**: 32 GB  
   - **CPU**: 4 cores / 8 threads (~1000 ST / ~3000 MT PassMark)  
   - **Bandwidth**: 50 Mbps down / 15 Mbps up